ASoC: sun4i-i2s: Use the physical / slot width for the clocks

ASoC: sun4i-i2s: Use the physical / slot width for the clocks

The clock dividers function has been using the word size to compute the
clock rate at which it's supposed to be running, but the proper formula
would be to use the physical width and / or slot width in TDM.

It doesn't make any difference at the moment since all the formats
supported have the same sample width and physical width, but it's not going
to last forever.

Fixes: 7d2993811a1e ("ASoC: sun4i-i2s: Add support for H3")
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://lore.kernel.org/r/41a359d9885f397e066816961e5e3236afcbe0a1.1566392800.git-series.maxime.ripard@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>