drm/ast: astdp: Test firmware status once during probing

Test for running ASTDP firmware during probe. Do not bother testing
this later. We cannot do much anyway if the firmware fails. Do not
initialize the ASTDP conenctor if the test fails during device probing.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reported-by: Shixiong Ou <oushixiong@kylinos.cn>
Tested-by: Shixiong Ou <oushixiong@kylinos.cn>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240717143319.104012-3-tzimmermann@suse.de