ALSA: fireface: support allocate_resources operation in ff400 protocol

ALSA: fireface: support allocate_resources operation in ff400 protocol

This commit is a part of preparation to perform allocation/release
of isochronous channels in pcm.hw_params/hw_free callbacks.

This commit implements allocate_resources callback for ff400 protocol.
In this callback, sampling transfer frequency is configured to the
device as well.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>