style: fix amd license and style issues

Change-Id: I26136fb49f743c4a597f8021cfd27f78897267b5
Reviewed-on: https://gem5-review.googlesource.com/10463
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>

gpu-compute: remove unused variable from scoreboard check stage

appease clang by removing the unused private member variable,
'numGlbMemPipes', from the scoreboard check stage

gpu-compute: AMD's baseline GPU model