[NVPTXAsmPrinter] do not print .align on function headers

Summary:
PTX does not allow .align directives on function headers.

Fixes PR21551.

Test Plan: test/Codegen/NVPTX/function-align.ll

Reviewers: eliben, jholewinski

Reviewed By: eliben, jholewinski

Subscribers: llvm-commits, eliben, jpienaar, jholewinski

Differential Revision: http://reviews.llvm.org/D8274

llvm-svn: 232004
diff --git a/llvm/lib/MC/MCAsmInfo.cpp b/llvm/lib/MC/MCAsmInfo.cpp
index 8a7ee94..bad257a 100644
--- a/llvm/lib/MC/MCAsmInfo.cpp
+++ b/llvm/lib/MC/MCAsmInfo.cpp
@@ -69,6 +69,7 @@
   HasAggressiveSymbolFolding = true;
   COMMDirectiveAlignmentIsInBytes = true;
   LCOMMDirectiveAlignmentType = LCOMM::NoAlignment;
+  HasFunctionAlignment = true;
   HasDotTypeDotSizeDirective = true;
   HasSingleParameterDotFile = true;
   HasIdentDirective = false;