The code has been rewritten to remove "generic" calls to
imx_pwm_{enable|disable|config}.

Such approach would facilitate switch to atomic PWM (a.k.a ->apply())
implementation.
Suggested-by: NStefan Agner <stefan@agner.ch>
Suggested-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: NStefan Agner <stefan@agner.ch>
Signed-off-by: NLukasz Majewski <l.majewski@majess.pl>
Reviewed-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>