[PATCH] Fix ARM unwind opcode assembler in several cases.

[Logan Chien]

  The changed test cases are:

  * test/CodeGen/ARM/ehabi-mc-section.ll
  * test/CodeGen/ARM/ehabi-mc.ll

  One unwind opcode was changed from "0x40" to "0x4a".  This opcode means that we have to add $sp by the offset.  The original result contains incorrect offset 0x40, which should be 0x4a instead.  I have verified the new result by comparing the output of:

  $ llc -mtriple armv7-unknown-linux-gnueabi -filetype=obj -arm-enable-ehabi -arm-enable-ehabi-descriptors -disable-fp-elim test/CodeGen/ARM/ehabi-mc-section.ll -o test-mc.o

  $ llc -mtriple armv7-unknown-linux-gnueabi -filetype=asm -arm-enable-ehabi -arm-enable-ehabi-descriptors -disable-fp-elim test/CodeGen/ARM/ehabi-mc-section.ll -o - | arm-linux-gnueabi-as -o test.o

http://llvm-reviews.chandlerc.com/D739