ASoC: wm8960: correct the max register value of mic boost pga
ASoC: wm8960: correct the max register value of mic boost pga

the max register value of mic boost pga should be 3.

Signed-off-by: Zidan Wang <3fcb6f8df82b54c7d117cf77f8dc10b524cd22a6@freescale.com>
Acked-by: Charles Keepax <8e4aa0015eb43ed5ca66aaca3fb498609e1e427c@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs