copy_svc is a little bit different from other copy helpers, OS stuff is
involved.  arm_linux_copy_svc itself has nothing to do with ARM/Thumb
mode.  It should work well under two modes.  However, one of the
parameters INSN make it hard to be called from both modes.  Fortunately,
INSN is *not* used inside arm_linux_copy_svc except printing debug
message.  We can remove parameter INSN and TO, so it can be called from
two modes respectively.

-- 
Yao (齐尧)