ALSA: ice1712: Fix boundary checks in PCM pointer ops

commit 4f8e940095536bc002a81666a4107a581c84e9b9 upstream.

PCM pointer callbacks in ice1712 driver check the buffer size boundary
wrongly between bytes and frames.  This leads to PCM core warnings
like:
   snd_pcm_update_hw_ptr0: 105 callbacks suppressed
   ALSA pcm_lib.c:352 BUG: pcmC3D0c:0, pos = 5461, buffer size = 5461, period size = 2730

This patch fixes these checks to be placed after the proper unit
conversions.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>