staging/xgifb: Rename XGI specific initdef.h defines

staging/xgifb: Rename XGI specific initdef.h defines

This patch renames some of the defines that exist in the sis initdef.h
but seem to have a different value.
In order to preserve the functionality of the driver, we simply prepend
these defines with XGI_ (for now) to resolve conflicts and review them
later on.

Renames:
SetCRT2ToLCDA -> XGI_SetCRT2ToLCDA
LCDVESATiming -> XGI_LCDVESATiming
EnableLVDSDDA -> XGI_EnableLVDSDDA
LCDDualLink  -> XGI_LCDDualLink
ModeSwitchStatus  -> XGI_ModeSwitchStatus
YPbPr750pVCLK  -> XGI_YPbPr750pVCLK

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