[clang][driver][NFC] Call IsARMBigEndain function only for isARM and isThumb.

IsARMBIgEndian function returns true only if:
  1. The triples are either arm or thumb and the
     commandline has the  option -mbig-endian
  2. The triples are either armeb or thumbeb.

Missing the checking of arm or thumb triples in the
first case pass through the --be8 endian flag to
linker For AArch64 as well which is not expected.
This is the regression happened from the previous
patch https://reviews.llvm.org/D154786.

It is better to refactor to only call IsARMBigEndian
for isARM and isthumb satisfying conditions which
keeps ARM and AArch64 separate.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D155808

Author: simpal01

clang/lib/Driver/ToolChains/BareMetal.cpp

@@ -443,12 +443,13 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
   CmdArgs.push_back("-Bstatic");
 
-  if (Triple.isARM() || Triple.isThumb() || Triple.isAArch64()) {
+  if (Triple.isARM() || Triple.isThumb()) {
     bool IsBigEndian = arm::isARMBigEndian(Triple, Args);
     if (IsBigEndian)
       arm::appendBE8LinkFlag(Args, CmdArgs, Triple);
-    IsBigEndian = IsBigEndian || Arch == llvm::Triple::aarch64_be;
     CmdArgs.push_back(IsBigEndian ? "-EB" : "-EL");
+  } else if (Triple.isAArch64()) {
+    CmdArgs.push_back(Arch == llvm::Triple::aarch64_be ? "-EB" : "-EL");
   }
 
   Args.AddAllArgs(CmdArgs,

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -424,12 +424,13 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   if (Args.hasArg(options::OPT_s))
     CmdArgs.push_back("-s");
 
-  if (Triple.isARM() || Triple.isThumb() || Triple.isAArch64()) {
+  if (Triple.isARM() || Triple.isThumb()) {
     bool IsBigEndian = arm::isARMBigEndian(Triple, Args);
     if (IsBigEndian)
       arm::appendBE8LinkFlag(Args, CmdArgs, Triple);
-    IsBigEndian = IsBigEndian || Arch == llvm::Triple::aarch64_be;
     CmdArgs.push_back(IsBigEndian ? "-EB" : "-EL");
+  } else if (Triple.isAArch64()) {
+    CmdArgs.push_back(Arch == llvm::Triple::aarch64_be ? "-EB" : "-EL");
   }
 
   // Most Android ARM64 targets should enable the linker fix for erratum