This issue was caught with assert checking enabled but is not a
functional bug as XINT(x, 0) happens to overlay INTVAL(x) anyway.

gcc/
	* config/mips/mips.c (mips_final_prescan_insn): Fix incorrect
	XINT with INTVAL.
	(mips_final_postscan_insn): Likewise.

From-SVN: r258099