drivers: audio: codec: Include errno.h in header

Header uses errno so include it right here.

Signed-off-by: Utsav Munendra <[email protected]>

Author: utsavm9

include/zephyr/audio/codec.h

@@ -24,6 +24,7 @@
  * @{
  */
 
+#include <errno.h>
 #include <zephyr/drivers/i2s.h>
 
 #ifdef __cplusplus