Fix the encoding of the armv7m (MClass) for MSR registers other than aspr,

Fix the encoding of the armv7m (MClass) for MSR registers other than aspr,
iaspr, espr and xpsr which also needed to have 0b10 in their mask encoding bits.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158560 91177308-0d34-0410-b5e6-96231b3b80d8