Add -flto-report-wpa

Add -flto-report-wpa

-flto-report is useful, but it prints for every LTRANS pass and
is very noisy and the main problem is often in WPA only.

Add a new -flto-report-wpa option that is only printed for WPA.

gcc/:

2013-04-22  Andi Kleen  <ak@linux.intel.com>

	* common.opt (-flto-report-wpa): Add.
	* doc/invoke.texi (-flto-report-wpa): Add.
	* lto/lto.c (do_whole_program_analysis): Check for lto-report-wpa.
	(lto_main): dito.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@198172 138bc75d-0d04-0410-961f-82ee72b054a4