msm: kgsl: Moving contents of mach/kgsl.h to linux/msm_kgsl.h

We already have another header - msm_kgsl.h in include/linux.
Removing the dependency in mach.

Change-Id: I03419ca805923bf41c1d0908382eb07c2d6bf66e
Signed-off-by: Shrenuj Bansal <shrenujb@codeaurora.org>