ALSA: hdmi - dont fail on extra nodes

The number of HDMI nodes is expected to go up in future.
So don't fail hard on seeing extra converter/pin nodes.

We can still operate safely on the nodes within
MAX_HDMI_CVTS/MAX_HDMI_PINS.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>