livepatch: use FTRACE_OPS_FL_IPMODIFY

Use the FTRACE_OPS_FL_IPMODIFY flag to prevent conflicts with other
ftrace users who also modify regs->ip.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>