[ALSA] SH7760 ASoC support

ALSA ASoC support for SH7760
This patch adds ALSA ASoC drivers for the Audio interfaces
of the SH7760 SoC:
Add driver for the SH7760 DMA engine (dmabrg)
Add AC97 driver for HAC unit(s) found on SH7760/SH7780
Add I2S driver for SSI unit(s) found on SH7760/SH7780
Add a generic SH7760-AC97 machine driver.
Hook it all up with the build system.

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>