x86: ivybridge: Add a way to get the HDA config setting

Add a way check to whether HD audio is enabled. Use ioctl() to avoid
adding too many unusual operations to PCH.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

include/pch.h

@@ -13,6 +13,9 @@
 
 /* All the supported PCH ioctls */
 enum pch_req_t {
+	/* Returns HDA config info if Azalia V1CTL enabled, -ENOENT if not */
+	PCH_REQ_HDA_CONFIG,
+
 	PCH_REQ_TEST1,		/* Test requests for sandbox driver */
 	PCH_REQ_TEST2,
 	PCH_REQ_TEST3,