When the driver is unloaded before the codec is bound, it still keeps
the runtime PM refcount up, and results in the unbalance.  This patch
covers these cases by introducing a flag indicating the runtime PM
initialization and handling the codec registration procedure more
properly.  It also fixes the missing input beep device as a gratis,
too.
Signed-off-by: Takashi Iwai <tiwai@suse.de>