boards/intel_adsp_ace15_mtpm: Update google AEC kconfigs

Update defaults to match existing hardware.  The topologies currently
have four channels of S32_LE DMIC input, but AEC can only handle two
at runtime, so set it here to prevent it from allocating needless
buffers.

Also disable the mock setting, it's already selected by COMP_STUBS

Signed-off-by: Andy Ross <andyross@google.com>

Author: andyross

app/boards/intel_adsp_ace15_mtpm.conf

@@ -94,4 +94,7 @@ CONFIG_PROBE=y
 CONFIG_PROBE_DMA_MAX=2
 CONFIG_KCPS_DYNAMIC_CLOCK_CONTROL=y
 CONFIG_COMP_GOOGLE_RTC_AUDIO_PROCESSING=y
+CONFIG_COMP_GOOGLE_RTC_AUDIO_PROCESSING_NUM_CHANNELS=2
+CONFIG_GOOGLE_RTC_AUDIO_PROCESSING_MIC_BITS=32
+
 CONFIG_COMP_STUBS=y