ASoC: alc5632: Remove unexisting route from Phone Mix to Mono Mix

There is no Phone Mix<->Mono Mix route in datasheet.

Signed-off-by: Andrey Danin <danindrey@mail.ru>
Signed-off-by: Leon Romanovsky <leon@leon.nu>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>