Introduced snd_card_create() function as a replacement of snd_card_new().
The new function returns a negative error code so that the probe callback
can return the proper error code, while snd_card_new() can give only NULL
check.

The old snd_card_new() is still provided as an inline function but with
__deprecated attribute.  It'll be removed soon later.
Signed-off-by: Takashi Iwai <tiwai@suse.de>