exynos4: Fix build of hwc and gralloc

HAL_PIXEL_FORMAT_RGBA_5551 and HAL_PIXEL_FORMAT_RGBA_4444 are used
by our hwc and gralloc, but they no longer exist in /system/core/include,
so we are moving these two formats to the hardware specific repo

Change-Id: I1c214af3b9819290173d2d60122d45a8ac635faf