sm6250-common: overlay: Configure number of physical SIM slots

Needed by telephony-common.

overlay/frameworks/base/core/res/res/values/config.xml

@@ -249,4 +249,11 @@
     <!-- When true use the linux /dev/input/event subsystem to detect the switch changes
          on the headphone/microphone jack. When false use the older uevent framework. -->
     <bool name="config_useDevInputEventForAudioJack">true</bool>
+
+    <!-- Number of physical SIM slots on the device. This includes both eSIM and pSIM slots, and
+         is not necessarily the same as the number of phones/logical modems supported by the device.
+         For example, a multi-sim device can have 2 phones/logical modems, but 3 physical slots,
+         or a single SIM device can have 1 phones/logical modems, but 2 physical slots (one eSIM
+         and one pSIM) -->
+    <integer name="config_num_physical_slots">2</integer>
 </resources>