sm8250-common: Add built-in/Back mic to primary input sources

Built-in mic and Built-In Back Mic aren't in supported devices
list of primary input, so record_24 is selected if without
connecting any headset, if there is more than 2 capture
concurrency, it will fail to open input for primary input when
connecting headset in AHAL.

Add built-in mic to primary input sources to reuse input to avoid
to open extra input stream in AHAL.

audio/audio_policy_configuration.xml

@@ -391,7 +391,7 @@ IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
                 <route type="mix" sink="voice_rx"
                        sources="Telephony Rx"/>
                 <route type="mix" sink="primary input"
-                       sources="Wired Headset Mic,BT SCO Headset Mic,USB Device In,USB Headset In,Telephony Rx"/>
+                       sources="Built-In Mic,Built-In Back Mic,Wired Headset Mic,BT SCO Headset Mic,USB Device In,USB Headset In,Telephony Rx"/>
                 <route type="mix" sink="hotword input"
                        sources="Built-In Mic,Built-In Back Mic,Wired Headset Mic,BT SCO Headset Mic,USB Device In,USB Headset In"/>
                 <route type="mix" sink="voip_tx"