vkEnumerateLayers: Update to match upstream

The upstream vulkan.h header removed maxLayerCount parameter
from vkEnumerateLayers. This patch implements that change
for the sample driver and layers.
diff --git a/vk-layer-generate.py b/vk-layer-generate.py
index fe76533..e97243b 100755
--- a/vk-layer-generate.py
+++ b/vk-layer-generate.py
@@ -492,10 +492,10 @@
                      '        fflush(stdout);\n'
                      '    %s'
                      '    } else {\n'
-                     '        if (pOutLayerCount == NULL || pOutLayers == NULL || pOutLayers[0] == NULL)\n'
+                     '        if (pLayerCount == NULL || pOutLayers == NULL || pOutLayers[0] == NULL)\n'
                      '            return VK_ERROR_INVALID_POINTER;\n'
                      '        // This layer compatible with all GPUs\n'
-                     '        *pOutLayerCount = 1;\n'
+                     '        *pLayerCount = 1;\n'
                      '        strncpy((char *) pOutLayers[0], "%s", maxStringSize);\n'
                      '        return VK_SUCCESS;\n'
                      '    }\n'
@@ -753,10 +753,10 @@
                      '        %s    %s    %s\n'
                      '    %s'
                      '    } else {\n'
-                     '        if (pOutLayerCount == NULL || pOutLayers == NULL || pOutLayers[0] == NULL)\n'
+                     '        if (pLayerCount == NULL || pOutLayers == NULL || pOutLayers[0] == NULL)\n'
                      '            return VK_ERROR_INVALID_POINTER;\n'
                      '        // This layer compatible with all GPUs\n'
-                     '        *pOutLayerCount = 1;\n'
+                     '        *pLayerCount = 1;\n'
                      '        strncpy((char *) pOutLayers[0], "%s", maxStringSize);\n'
                      '        return VK_SUCCESS;\n'
                      '    }\n'
@@ -1209,10 +1209,10 @@
                      '    %s%s'
                      '    %s'
                      '    } else {\n'
-                     '        if (pOutLayerCount == NULL || pOutLayers == NULL || pOutLayers[0] == NULL)\n'
+                     '        if (pLayerCount == NULL || pOutLayers == NULL || pOutLayers[0] == NULL)\n'
                      '            return VK_ERROR_INVALID_POINTER;\n'
                      '        // This layer compatible with all GPUs\n'
-                     '        *pOutLayerCount = 1;\n'
+                     '        *pLayerCount = 1;\n'
                      '        strncpy((char *) pOutLayers[0], "%s", maxStringSize);\n'
                      '        return VK_SUCCESS;\n'
                      '    }\n'
@@ -1349,10 +1349,10 @@
                      '        fflush(stdout);\n'
                      '    %s'
                      '    } else {\n'
-                     '        if (pOutLayerCount == NULL || pOutLayers == NULL || pOutLayers[0] == NULL)\n'
+                     '        if (pLayerCount == NULL || pOutLayers == NULL || pOutLayers[0] == NULL)\n'
                      '            return VK_ERROR_INVALID_POINTER;\n'
                      '        // This layer compatible with all GPUs\n'
-                     '        *pOutLayerCount = 1;\n'
+                     '        *pLayerCount = 1;\n'
                      '        strncpy((char *) pOutLayers[0], "%s", maxStringSize);\n'
                      '        return VK_SUCCESS;\n'
                      '    }\n'