ALSA: ice1712: Fix boundary checks in PCM pointer ops

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.

Change-Id: Ibe8a2aba731fc17c4516e724cbc6b4f3f5866048
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>