cfgcleanup.c, [...]: Fix comment typos.

	* cfgcleanup.c, config/dfp-bit.c, expr.c, fold-const.c,
	jump.c, mips-tfile.c, omp-low.c, sched-int.h,
	tree-ssa-loop-prefetch.c, tree-vrp.c: Fix comment typos.

From-SVN: r112971