remove all references to pmem and simplify the lock/unlock hooks

this gralloc module is only used on the emulator or without a h/w
renderer. therefore there is no synchronization to do in lock/unlock
and pmem buffers are not relevant.

hopefully this will remove some of the confusion about how gralloc
should be implemented and make it more obvious that this implementation
is not intended to be used by h/w renderers.
diff --git a/modules/gralloc/framebuffer.cpp b/modules/gralloc/framebuffer.cpp
index 7d2b582..0195103 100644
--- a/modules/gralloc/framebuffer.cpp
+++ b/modules/gralloc/framebuffer.cpp
@@ -92,18 +92,8 @@
     private_handle_t const* hnd = reinterpret_cast<private_handle_t const*>(buffer);
     private_module_t* m = reinterpret_cast<private_module_t*>(
             dev->common.module);
-    
-    if (m->currentBuffer) {
-        m->base.unlock(&m->base, m->currentBuffer);
-        m->currentBuffer = 0;
-    }
 
     if (hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER) {
-
-        m->base.lock(&m->base, buffer, 
-                private_module_t::PRIV_USAGE_LOCKED_FOR_POST, 
-                0, 0, m->info.xres, m->info.yres, NULL);
-
         const size_t offset = hnd->base - m->framebuffer->base;
         m->info.activate = FB_ACTIVATE_VBL;
         m->info.yoffset = offset / m->finfo.line_length;
@@ -292,8 +282,7 @@
 
     int err;
     size_t fbSize = roundUpToPageSize(finfo.line_length * info.yres_virtual);
-    module->framebuffer = new private_handle_t(dup(fd), fbSize,
-            private_handle_t::PRIV_FLAGS_USES_PMEM);
+    module->framebuffer = new private_handle_t(dup(fd), fbSize, 0);
 
     module->numBuffers = info.yres_virtual / info.yres;
     module->bufferMask = 0;