ASoC: dapm: Consistently use unsigned int for register values

Commit f7d3c170 ("ASoC: dapm: Change prototype of soc_widget_read") changed the
signature of soc_widget_read() so that it, instead of return the register value
as a int, takes a pointer to a unsigned int and stores the register value in
that pointer. There are still a few places that pass a int type value to that
function though. Change these to unsigned int. For more consistency also change
the signature of soc_widget_write() to take a unsigned int instead of an int for
the register value.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>