ALSA: Fix compat_ioctl handling for OSS emulations

The ALSA PCM, mixer and sequencer OSS emulations provide the 32bit
compatible ioctl, but they just call the 64bit native ioctl as is.
Although this works in most cases, passing the argument value as-is
isn't guaranteed to work on all architectures.  We need to convert it
via compat_ptr() instead.

This patch addresses the missing conversions.  Since all relevant
ioctls in these functions take the argument as a pointer, we do the
pointer conversion in each compat_ioctl and pass it as a 64bit value
to the native ioctl.

Signed-off-by: Takashi Iwai <tiwai@suse.de>