libc2dcolorconvert: Add compatibility with older libc2d

The C2D implementation on Adreno200 either lacks the map/unmap
functions, or returns invalid values, so fallback to the direct
usage of /dev/kgsl nodes to map GPU memory when the symbols are
absent.

Change-Id: I243d2ef6f4257bace2c785230d71cd032a5b6a09