staging/xgifb: Remove unnecessary binary calculation in GetXG27FPBits

If temp <= 2 no other bits than the lowest two (0x03) can be set anyway
-> this operation can be removed.

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