Mic PGA Switch should be inverted in the WM8510 driver but isn't.

Reported-by: ext-jukka.hynninen@vaisala.com
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@perex.cz>