ASoC: codecs: allow compile testing without MFD drivers

Motorola CPCAP, Lochnagar Sound, Rockchip RK817 and Qualcomm
WCD9340/WCD9341 do not depend on parent MFD driver in build time and can
be compile tested without respective MFD part for increased build
coverage.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220826093659.1059276-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>