Replace sRGB_888 with sRGB_X_8888

As sRGB_888 is not defined, replace it with sRGB_X_8888

Change-Id: Ie7e27ffea1ca6ec99de8e746c0f784e5fc9a4e53
(cherry picked from commit b81796dc9a0c4178004ae947e9d756c5cae6967a)
diff --git a/libgralloc/gpu.cpp b/libgralloc/gpu.cpp
index 2b123dd..eb19f89 100644
--- a/libgralloc/gpu.cpp
+++ b/libgralloc/gpu.cpp
@@ -173,7 +173,7 @@
 {
     *bufferType = BUFFER_TYPE_VIDEO;
 
-    if (inputFormat <= HAL_PIXEL_FORMAT_sRGB_888) {
+    if (inputFormat <= HAL_PIXEL_FORMAT_sRGB_X_8888) {
         // RGB formats
         *bufferType = BUFFER_TYPE_UI;
     } else if ((inputFormat == HAL_PIXEL_FORMAT_R_8) ||