[ARC] Fix ld testsuite failures.

[ARC] Fix ld testsuite failures.

ld/
016-04-05  Cupertino Miranda  <cmiranda@synopsys.com>

	* testsuite/ld-discard/extern.d: Removed xfail for ARC.
	* testsuite/ld-discard/start.d: Likewise.
	* testsuite/ld-discard/static.d: Likewise.
	* testsuite/ld-elf/group1.d: Likewise.
	* testsuite/ld-elf/group3b.d: Likewise.
	* testsuite/ld-elf/orphan-region.d: Likewise.
	* testsuite/ld-elf/orphan.d: Likewise.
	* testsuite/ld-elf/orphan3.d: Likewise.
	* testsuite/ld-elf/pr349.d: Likewise.
	* testsuite/ld-elf/warn1.d: Likewise.
	* testsuite/ld-elf/warn2.d: Likewise.
	* testsuite/ld-elf/warn3.d: Likewise.
	* testsuite/ld-scripts/crossref.exp: Add __SDATA_BEGIN__ symbol
	through linker flags.
	* testsuite/ld-srec/srec.exp: Set as xfail.