x86/mce: Mark mce_panic() noinstr

And allow instrumentation inside it because it does calls to other
facilities which will not be tagged noinstr.

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xc73: call to mce_panic() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-8-bp@alien8.de