ASoC: wcd: Modify the subsystem status check in probe function

Wcd codec probe is deferred, if the subsystem status is not loaded.
Only a successful driver probe triggers the deferred driver
functions. Subsystem status is set to LOADED from adsp loader
function. If there are no successful driver probes after this,
then wcd probe never been called and sound card registration failed.

Modify the status check in the probe function, such that if subsystem
status is up, probe the wcd codec driver. Subsystem status is
updated in APR function, upon subsystem notifier callback.

Change-Id: I596af8a2f362741d526561f02bd9ad0dfd5612f9
Signed-off-by: Viraja Kommaraju <virajak@codeaurora.org>