ALSA: hda_hwdep: Fix possible buffer overflow

If a line in the firmware file is larger than the given buffer size (and
so the firmware file size), size is set to a value larger than the actual
buffer size. This results in an overflow in the buffer passed.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>