[MC] Fix -stack-size-section on ARM

Change symbol values in the stack_size section from being 8 bytes, to being a target dependent size.

Differential Revision: https://reviews.llvm.org/D42108

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322619 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed