ASoC: atmel: mchp-spdifrx needs COMMON_CLK

Compile-testing this driver on an older platform without CONFIG_COMMON_CLK fails with

ERROR: modpost: "clk_set_min_rate" [sound/soc/atmel/snd-soc-mchp-spdifrx.ko] undefined!

Make this is a strict dependency.

Fixes: ef265c55

 ("ASoC: mchp-spdifrx: add driver for SPDIF RX")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Link: https://lore.kernel.org/r/20201203223815.1353451-1-arnd@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>