Sound: Add command for audio playback

This patch adds command to test audio playback.
sound init - Initialises the audio subsystem (i2s and wm8994 codec)
sound play - Plays predefined the audio data when specified length
and frequency.

Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/common/Makefile b/common/Makefile
index 9e43322..ded6318 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -75,6 +75,7 @@
 COBJS-$(CONFIG_CMD_CPLBINFO) += cmd_cplbinfo.o
 COBJS-$(CONFIG_DATAFLASH_MMC_SELECT) += cmd_dataflash_mmc_mux.o
 COBJS-$(CONFIG_CMD_DATE) += cmd_date.o
+COBJS-$(CONFIG_CMD_SOUND) += cmd_sound.o
 ifdef CONFIG_4xx
 COBJS-$(CONFIG_CMD_SETGETDCR) += cmd_dcr.o
 endif