ALSA: lx6464es - fix device communication via command bus

commit 6175ddf0 optimized the mem*io
functions that have been used to send commands to the device. these
optimizations somehow corrupted the communication with the lx6464es,
that resulted the device to be unusable with kernels after 2.6.33.

this patch emulates the memcpy_*_io functions via a loop to avoid these
problems.

Signed-off-by: Tim Blechmann <tim@klingt.org>
LKML-Reference: <4ECB5257.4040600@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>