[ms-inline asm] Add support for parsing complex immediate expressions.  Test
cases to be submitted on clang side shortly.
rdar://13663768 and PR15760

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179655 91177308-0d34-0410-b5e6-96231b3b80d8
Mips assembler: Enable handling of nested expressions

This patch allows the Mips assembler to parse and emit nested 
expressions as instruction operands. It also extends the 
expansion of memory instructions when an offset is given as 
an expression. 

Contributer: Vladimir Medic



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179657 91177308-0d34-0410-b5e6-96231b3b80d8