Input: serio - define serio_pause_rx guard to pause and resume serio ports

Input: serio - define serio_pause_rx guard to pause and resume serio ports

serio_pause_rx() and serio_continue_rx() are usually used together to
temporarily stop receiving interrupts/data for a given serio port.
Define "serio_pause_rx" guard for this so that the port is always
resumed once critical section is over.

Example:

	scoped_guard(serio_pause_rx, elo->serio) {
		elo->expected_packet = toupper(packet[0]);
		init_completion(&elo->cmd_done);
	}

Link: https://lore.kernel.org/r/20240905041732.2034348-2-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>