Recent compilers produce a harmless warning for the new pcm_call_notify()
macro when CONFIG_SND_PCM_OSS is disabled:
sound/core/pcm.c: In function 'snd_pcm_free':
sound/core/pcm.c:905:37: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body]
This turns the empty macro into a 'do {} while (0)' statement to avoid
the warning.
Fixes: 58f30d650c ("ALSA: pcm: Build pcm notifier code conditionally")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
9aee03f39c