[RISCV][MC] Reject bare symbols for the simm12 operand type

addi a0, a0, foo and lw a0, foo(a0) and similar are now rejected. An explicit 
%lo and %pcrel_lo modifier is required. This matches gas behaviour.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342487 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed