Fix the encoding of the armv7m (MClass) for MSR APSR writes which was missing

Fix the encoding of the armv7m (MClass) for MSR APSR writes which was missing
the 0b10 mask encoding bits.  Make MSR APSR writes without a _<bits> qualifier
an alias for MSR APSR_nzcvq even though ARM as deprecated it use.  Also add
support for suffixes (_nzcvq, _g, _nzcvqg) for APSR versions.  Some FIXMEs in
the code for better error checking when versions shouldn't be used.
rdar://11457025

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157019 91177308-0d34-0410-b5e6-96231b3b80d8