ubsan: rx-parse.y:1743 shift exponent 32 is too large

ubsan: rx-parse.y:1743 shift exponent 32 is too large

	* config/rx-parse.y (rx_intop): Avoid too large shifts.
	(rx_intop, rx_uintop, rx_disp3op, rx_disp5op, displacement),
	(rtsd_immediate): Use correctly typed unsigned variables.