wlcore: Add missing PM call for wlcore_cmd_wait_for_event_or_timeout()

Otherwise we can get:

WARNING: CPU: 0 PID: 55 at drivers/net/wireless/ti/wlcore/io.h:84

I've only seen this few times with the runtime PM patches enabled
so this one is probably not needed before that. This seems to
work currently based on the current PM implementation timer. Let's
apply this separately though in case others are hitting this issue.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>