[ALSA] soc - s3c24xx - Improve diagnostic output

Add some debug messages for suspend/resume and to add a clear prefix to
s3c24xx-i2s and s3c24xx-pcm.

Signed-off-by: Tim Niemeyer <reddog@mastersword.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>