x86/alternatives: Lockdep-enforce text_mutex in text_poke*()

x86/alternatives: Lockdep-enforce text_mutex in text_poke*()

text_poke() and text_poke_bp() must be called with text_mutex held.

Put proper lockdep anotation in place instead of just mentioning the
requirement in a comment.

Reported-by: Peter Zijlstra <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Masami Hiramatsu <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]