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

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

	* cfglayout.c, config/arm/arm.c, config/arm/cortex-a8.md,
	config/arm/neon-schedgen.ml, config/arm/neon.ml,
	config/arm/vec-common.md, config/ia64/div.md, cselib.c,
	df-core.c, df.h, dominance.c, optabs.c, opts.c, reg-stack.c,
	regstat.c, target.h, tree-ssa-live.c, tree-ssa-pre.c,
	tree-vect-transform.c, tree.def: Fix comment typos.  Follow
	spelling conventions.
	* doc/invoke.texi: Follow spelling conventions.

From-SVN: r127030