staging/xgifb: Remove always false if statement

MCLKData does not contain any 0x1C value for its field SR28 nor does
XGI340_ECLKData contain any 0x1C or 0x22 value for its field SR2E.

-> the statement always evaluates to false.
-> remove

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