Build: fixed compiler warnings at gst_mfx_plugin_base_decide_allocation
Build: fixed compiler warnings at gst_mfx_plugin_base_decide_allocation

Fixes #14

Signed-off-by: Lim Siew Hoon <e412356d7e67dbdde94e841e5d46937fb9f4e623@intel.com>

rislim/gstreamer-media-SDK,rislim/gstreamer-media-SDK,ph0b/gstreamer-media-SDK,ishmael1985/gstreamer-media-SDK