Merge commit bc4bc5aa0 from llvm git (by Justin Hibbits):

Merge commit bc4bc5aa0 from llvm git (by Justin Hibbits):

  Add 8548 CPU definition and attributes

  8548 CPU is GCC's name for the e500v2, so accept this in clang.  The
  e500v2 doesn't support lwsync, so define __NO_LWSYNC__ for this as
  well, as GCC does.

  Differential Revision:  https://reviews.llvm.org/D67787

Merge commit ff0311c4b from llvm git (by Justin Hibbits):

  [PowerPC]: Add powerpcspe target triple subarch component

  Summary:
  This allows the use of '-target powerpcspe-unknown-linux-gnu' or
  'powerpcspe-unknown-freebsd' to be used, instead of '-target
  powerpc-unknown-linux-gnu -mspe'.

  Reviewed By: dim
  Differential Revision: https://reviews.llvm.org/D72014

Merge commit ba91dffaf from llvm git (by Fangrui Song):

  [Driver][PowerPC] Move powerpcspe logic from cc1 to Driver

  Follow-up of D72014. It is more appropriate to use a target feature
  instead of a SubTypeArch to express the difference.

  Reviewed By: #powerpc, jhibbits

  Differential Revision: https://reviews.llvm.org/D72433

commit 36eedfcb3 from llvm git (by Justin Hibbits):

  [PowerPC] Fix powerpcspe subtarget enablement in llvm backend

  Summary:

  As currently written, -target powerpcspe will enable SPE regardless
  of disabling the feature later on in the command line.  Instead,
  change this to just set a default CPU to 'e500' instead of a generic
  CPU.

  As part of this, add FeatureSPE to the e500 definition.

  Reviewed By: MaskRay
  Differential Revision: https://reviews.llvm.org/D72673

These are needed to unbreak the build for powerpcspe.

Requested by:	jhibbits
MFC after:	1 week