[DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame.

[DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame.

It is necessary to generate fixups in .debug_frame or .eh_frame as
relaxation is enabled due to the address delta may be changed after
relaxation.

There is an opcode with 6-bits data in debug frame encoding. So, we
also need 6-bits fixup types.

Differential Revision: https://reviews.llvm.org/D58335

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366442 91177308-0d34-0410-b5e6-96231b3b80d8