For allowing adjusting the timestamp type on the fly, add it to
sw_params.  The existing ioctl is still kept for compatibility.

Along with this, increment the PCM protocol version.

The extension was suggested by Clemens Ladisch.
Acked-by: NJaroslav Kysela <perex@perex.cz>
Reviewed-by: NMark Brown <broonie@linaro.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>