Now we support FTRACE_WITH_REGS with -fpatchable-function-entry, here
enable the livepatch support depend on FTRACE_WITH_REGS.

Use task flag bit 6 to track patch transisiton state for the consistency
model. Add it to the work mask so it gets cleared on all kernel exits to
userland.

Tell livepatch regs->pc + 2*AARCH64_INSN_SIZE is the place to change the
return address.

these codes have a big change against reference link, beacause we use new
gcc featrue.

References:
https://patchwork.kernel.org/patch/10657431/

Based-on-code-from: Torsten Duwe <duwe@suse.de>
Signed-off-by: NZou Cao <zoucao@linux.alibaba.com>
Acked-by: NCaspar Zhang <caspar@linux.alibaba.com>