ALSA: oxfw: rename a file for control elements so that it's for model-specific

ALSA: oxfw: rename a file for control elements so that it's for model-specific

In ALSA firewire stack, drivers basically has no control elements. This
is due to the fact that each model has own functionality even if they use
the same communication chipset. Implementing all of the functionalities in
kernel space unreasonably increases our efforts to maintain the stack. In
most case, these functionalities can be implemented in userspace via Linux
fw character devices.

However, ALSA OXFW driver has control elements comes from old
firewire-speakers driver. Adding the elements is in a file names as
'oxfw-control.c', while the elements are really model-specific. The
name is confusing because it gives an idea to handle control elements
for all of OXFW-based models.

This commit renames the file so that it's just for models supported by
old firewire-speakers driver.

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