x86/alternatives: Remove the mixed-patching restriction on smp_text_poke_single()

x86/alternatives: Remove the mixed-patching restriction on smp_text_poke_single()

At this point smp_text_poke_single(addr, opcode, len, emulate) is equivalent to:

	smp_text_poke_batch_add(addr, opcode, len, emulate);
	smp_text_poke_batch_finish();

So remove the restriction on mixing single-instruction patching
with multi-instruction patching.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250411054105.2341982-37-mingo@kernel.org