[mips] Remove XFAIL from test-ptr-reloc-remote.ll

The change r187019 has fixed multiple relocations in dynamic linker for
MIPS, so now this test passes for MIPS.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187053 91177308-0d34-0410-b5e6-96231b3b80d8