[ms-abi] Fixing bitfields sema arror for ms-mode

The check for bitfields that are longer than their base type needed to 
be checked in microsoft mode (cl.exe does not support the C++ extnetion 
for bitfields longer than their type).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197186 91177308-0d34-0410-b5e6-96231b3b80d8