msm8974: Honor input_mic_max_count property when set to 1.

The default value of max_mic_count is 2. max_mic_count is set to
the value specified by the input_mic_max_count property in
audio_platform_info.xml.

Honor the input_mic_max_count property when set to 1. Prior to
this change when max_mic_count this value is 1, the
'source_mic_type' includes SOURCE_DUAL_MIC. For the single mic
case, we don't want that.

Bug: 71773847
Test: Recording on a device with a single microphone uses
      single-mic paths instead of dual mic paths when recording
      flucence/voice or when specifying two mics.

Change-Id: I2b3be6333d4c58a611026ad63bc4178dca0a13ca