staging/xgifb: Remove unnecessary bitshifts in XGI_SetCRT1ModeRegs

Since data can only be 0x0000, 0x0035 or 0x0048 we can simply skip the
bit shifting and masking as data & 0xFF is always equal to data and
data & 0xFF00 is always 0.
So we simply use data and 0 directly and save the assignment.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>