ALSA: pcm: oss: Fix negative period/buffer sizes

The period size calculation in OSS layer may receive a negative value
as an error, but the code there assumes only the positive values and
handle them with size_t.  Due to that, a too big value may be passed
to the lower layers.

This patch changes the code to handle with ssize_t and adds the proper
error checks appropriately.

Reported-by:  <syzbot+bb348e9f9a954d42746f@syzkaller.appspotmail.com>
Reported-by: Bixuan Cui <cuibixuan@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1638270978-42412-1-git-send-email-cuibixuan@linux.alibaba.com
Link: https://lore.kernel.org/r/20211201073606.11660-2-tiwai@suse.de


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