[PowerPC] Support @tls in the asm parser

This adds support for the last missing construct to parse TLS-related
assembler code:
   add 3, 4, symbol@tls

The ADD8TLS currently hard-codes the @tls into the assembler string.
This cannot be handled by the asm parser, since @tls is parsed as
a symbol variant.  This patch changes ADD8TLS to have the @tls suffix
printed as symbol variant on output too, which allows us to remove
the isCodeGenOnly marker from ADD8TLS.  This in turn means that we
can add a AsmOperand to accept @tls marked symbols on input.

As a side effect, this means that the fixup_ppc_tlsreg fixup type
is no longer necessary and can be merged into fixup_ppc_nofixup.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185692 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPC.h b/lib/Target/PowerPC/PPC.h
index d5a08ee..96b882a 100644
--- a/lib/Target/PowerPC/PPC.h
+++ b/lib/Target/PowerPC/PPC.h
@@ -85,7 +85,10 @@
     /// into memory operations.
     MO_DTPREL_LO = 5 << 4,
     MO_TLSLD_LO  = 6 << 4,
-    MO_TOC_LO    = 7 << 4
+    MO_TOC_LO    = 7 << 4,
+
+    // Symbol for VK_PPC_TLS fixup attached to an ADD instruction
+    MO_TLS       = 8 << 4
   };
   } // end namespace PPCII