Relands #132907 with a fix in the testcase:
clang/test/CodeGen/Mips/subtarget-feature-test.c
enable this test for only mips64 target
PR #130587 defined same SubTargetFeature for CPUs i6400 and i6500 which
resulted into following warning when -mcpu=i6500 was used:
+i6500' is not a recognized feature for this target (ignoring feature)
This PR fixes above issue by defining separate SubTargetFeature for
i6500.
1318a7bb09