staging/xgifb: Remove redundant if statement

The code checks twice for if (pVBInfo->VBInfo & SetCRT2ToTV) without any
changes in between -> we can remove the second check.
And while at it we can also save the temp variable and use tempbx
directly.

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