disp: msm: sde: make all HW definitions unsigned

Treating hw version as a signed int results in a negative
number when major version is more than 7, leading to errors
when comparing versions in the driver. Fix this by making
sure all HW version definitions and variables are unsigned.

Change-Id: Ic77183f85e5408092e05817cf95df5b0f0fcac75
Signed-off-by: Nilaan Gunabalachandran <ngunabal@codeaurora.org>