This fixes the Thumb2 CPS assembly syntax.

In Thumb1, only one variant is supported: CPS{effect} {flags}

Thumb2 supports three:
CPS{effect}.W {flags}
CPS{effect} {flags} {mode}
CPS {mode}

Canonically, .W should be used only when ambiguity is present between encodings of different width.
The wide suffix is still accepted for the latter two forms via aliases.

llvm-svn: 188071