drm: bridge/dw_hdmi-ahb-audio: parse ELD from HDMI driver

Parse the ELD (EDID like data) stored from the HDMI driver to restrict
the sample rates and channels which are available to ALSA.  This causes
the ALSA device to reflect the capabilities of the overall audio path,
not just what is supported at the HDMI source interface level.

Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/gpu/drm/bridge/Kconfig

@@ -15,6 +15,7 @@ config DRM_DW_HDMI_AHB_AUDIO
 	tristate "Synopsis Designware AHB Audio interface"
 	depends on DRM_DW_HDMI && SND
 	select SND_PCM
+	select SND_PCM_ELD
 	select SND_PCM_IEC958
 	help
 	  Support the AHB Audio interface which is part of the Synopsis