alsa_sound: Allow SPEAKER_DUAL_MIC_* UCMs with USES_FLUENCE_INCALL

Enables SND_USE_CASE_DEV_SPEAKER_DUAL_MIC_* UCMs when using speakerphone
with USES_FLUENCE_INCALL defined.  This allows devices to use different
DMIC settings for earpiece and speakerphone modes.

Devices that wish to retain the old behavior should clone the DUAL_MIC_*
UCMs for SPEAKER_DUAL_MIC_*.