ASoC: fsl/mxs: Remove unnecessarily gendered language

The kernel as a number of cases of gendered language. The majority of these
refer to objects that don't have gender in English, and so I've replaced
them with "it" and "its". Some refer to people (developers or users), and
I've replaced these with the singular "they" variant. Some are simply
typos that I've fixed up.

I've left cases where gendered language was used to refer to specific
individuals, was a quote or is part of license text.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Mark Brown <broonie@linaro.org>