[ARM GlobalISel] Fix call opcodes

[ARM GlobalISel] Fix call opcodes

We were generating BLX for all the calls, which was incorrect in most
cases. Update ARMCallLowering to generate BL for direct calls, and BLX,
BX_CALL or BMOVPCRX_CALL for indirect calls.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316570 91177308-0d34-0410-b5e6-96231b3b80d8