ALSA: hdsp: check for iobox and upload firmware during ioctl

currently, the error message when trying to run hdspmixer or hdspconf
if the breakout box is not connected is somehow misleading, since it
asks the user to upload the firmware.

this patch adds a test, whether the breakout box is connected and
tries to upload the firmware in the case, that it is not present, e.g.
because of power failures of the breakout box.

[Minor coding-style fixes by tiwai]

Signed-off-by: Tim Blechmann <tim@klingt.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>