ASoC: wm8960: Fix the Input PGA Mute switch

Change the xinvert value from 0 to 1 on the "Capture Switch" control
WM8960 datasheet is shown as follows:
Bit 7 at 00h and 01h register address
1 : Enable Mute, 0 : Disable Mute

Signed-off-by: JongHo Kim <furmuwon@gmail.com>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>