Add cfi directives to all arm assembly.

Add cfi directives to all arm assembly.

Since the ENTRY/END macros now have .cfi_startproc/.cfi_endproc, most of the
custom arm assembly has no unwind information. Adding the proper cfi directives
for these and removing the arm directives.

Update the gensyscalls.py script to add these cfi directives for the generated
assembly. Also fix the references to non-uapi headers to the proper uapi
header.

In addition, remove the kill.S, tkill.S, tgkill.S for arm since they are not
needed at all. The unwinder (libunwind) is able to properly unwind using the
normal abort.

After this change, I can unwind through the system calls again.

Bug: 11559337
Bug: 11825869
Bug: 11321283

Change-Id: I18b48089ef2d000a67913ce6febc6544bbe934a3