Convert mov foo@GOT(%reg), %reg to lea foo@GOTOFF(%reg), %reg

Convert mov foo@GOT(%reg), %reg to lea foo@GOTOFF(%reg), %reg

2015-04-01  Ilya Tocar  <ilya.tocar@intel.com>

	PR gold/17640
	* i386.cc (Target_i386::can_convert_mov_to_lea): New.
	(Target_i386::Scan::local): Don't create GOT entry, when we
	can convert GOT to GOTOFF.
	(Target_i386::Scan::global): Ditto.
	(Target_i386::Relocate::relocate): Convert  mov foo@GOT(%reg), %reg to
	lea foo@GOTOFF(%reg), %reg if possible.
	* testsuite/Makefile.am (i386_mov_to_lea): New test.
	* testsuite/i386_mov_to_lea1.s: New.
	* testsuite/i386_mov_to_lea2.s: Ditto.
	* testsuite/i386_mov_to_lea3.s: Ditto.
	* testsuite/i386_mov_to_lea4.s: Ditto.
	* testsuite/i386_mov_to_lea5.s: Ditto.
	* testsuite/i386_mov_to_lea.sh: Ditto.