msm: kgsl: Get GMU version information from FW image

The GMU FW now contains version information in the block headers.
Save this data from the FW image to easily identify what GMU
FW image is being used.

Change-Id: I15ba738311ae39824a0b0a469e54865711fcd0c3
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>