common.opt (feliminate-dwarf2-dups): Replace references to "DWARF 2" with just "DWARF".

common.opt (feliminate-dwarf2-dups): Replace references to "DWARF 2" with just "DWARF".

2016-01-20  Sandra Loosemore <sandra@codesourcery.com>

	gcc/
	* common.opt (feliminate-dwarf2-dups): Replace references to
	"DWARF 2" with just "DWARF".
	* config/ia64/ia64.opt (mdwarf2-asm): Likewise.
	* doc/extend.texi: Likewise.
	* doc/cpp.texi: Likewise.
	* doc/invoke.texi: Likewise.
	(Option Summary): Add -gdwarf to list of Debugging Options.
	(Debugging Options): Document -gdwarf.
	* doc/contrib.texi: Spell "DWARF" like that.

From-SVN: r232647