position_fix=3 is the option to correct the DMA position with the
FIFO size.  But, it never worked correctly, and we have now more other
workarounds for the DMA position fixes.  Thus better to remove it.

Also, change POS_FIX_NONE to POS_FIX_LPIB to represent its real role
better.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@perex.cz>