Do not XFAIL test/tools/llvm-cov tests on powerpc64le

All tests in test/tools/llvm-cov fail on big-endian targets and are
supposed to be XFAILed there.  However, including "powerpc64" in the
XFAIL line is now incorrect, since that matches both powerpc64- and
powerpc64le- targets, and the tests pass on the latter.

Update the XFAIL lines to use powerpc64- instead (like mips64-).

llvm-svn: 211172
diff --git a/llvm/test/tools/llvm-cov/llvm-cov.test b/llvm/test/tools/llvm-cov/llvm-cov.test
index 2345f8d..82d1273 100644
--- a/llvm/test/tools/llvm-cov/llvm-cov.test
+++ b/llvm/test/tools/llvm-cov/llvm-cov.test
@@ -110,4 +110,4 @@
 # Bad function checksum on gcda
 RUN: not llvm-cov test.c -gcda=test_func_checksum_fail.gcda
 
-XFAIL: powerpc64, s390x, mips-, mips64-, sparc
+XFAIL: powerpc64-, s390x, mips-, mips64-, sparc