[ALSA] sound/core/control.c: hard-irq-safe -> hard-irq-unsafe lock warning

The lock grabbed in snd_ctl_empty_read_queue() is hardirq-unsafe but we hold
an hardirq-safe one already, so make the &ctl->read_lock also hard-irq-safe.

Signed-off-by: Borislav Petkov <bbpetkov@yahoo.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>