ALSA: cs35l41: Check hw_config before using it

The driver can receive an empty hw_config, so mark as valid if
successfully read from device tree/ACPI or set by the driver itself.
Platforms not marked with a valid hw config will not be supported.

Signed-off-by: Lucas Tanure <tanureal@opensource.cirrus.com>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220413083728.10730-3-tanureal@opensource.cirrus.com


Signed-off-by: Takashi Iwai <tiwai@suse.de>