msm: kgsl: Report GMU firmware failure up the stack

Report and error if the firmware is not compatible. Pass
the error code back to the main GMU driver so it can try
to handle the error properly (rather than just blindly
continuing on).

Change-Id: I4f41419403fca91c2ba5b26a696cb59cd276f95b
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>