bearch: Remove unnecessary test in arch_perform_memory_operand().
bearch: Remove unnecessary test in arch_perform_memory_operand().

When arch_perform_memory_operand() returned a positive result before, there really should be a callback to actually perform the action.

libfirm/libfirm,MatzeB/libfirm,MatzeB/libfirm,8l/libfirm,killbug2004/libfirm,killbug2004/libfirm,8l/libfirm,davidgiven/libfirm,killbug2004/libfirm,davidgiven/libfirm,jonashaag/libfirm,jonashaag/libfirm,jonashaag/libfirm,jonashaag/libfirm,davidgiven/libfirm,libfirm/libfirm,libfirm/libfirm,8l/libfirm,libfirm/libfirm,killbug2004/libfirm,jonashaag/libfirm,davidgiven/libfirm,MatzeB/libfirm,8l/libfirm,MatzeB/libfirm,davidgiven/libfirm,killbug2004/libfirm,8l/libfirm,MatzeB/libfirm,MatzeB/libfirm,8l/libfirm,killbug2004/libfirm,davidgiven/libfirm,davidgiven/libfirm,jonashaag/libfirm,jonashaag/libfirm,8l/libfirm,killbug2004/libfirm,MatzeB/libfirm,libfirm/libfirm