ril: allow ril to set vendor.radio.sim_num.switch

Used for reboot-free-dsds

Bug: 143519042
Test: SIM switch from SSIM to DSDS
      SIM switch from DSDS to SSIM

Change-Id: I8400dac1c3afc37295feb454bc3e70195e677f7b
diff --git a/vendor/qcom/common/property_contexts b/vendor/qcom/common/property_contexts
index eb3f7de..14cc38e 100644
--- a/vendor/qcom/common/property_contexts
+++ b/vendor/qcom/common/property_contexts
@@ -176,6 +176,7 @@
 persist.vendor.radio.simlock.list  u:object_r:vendor_radio_prop:s0
 ro.radio.log_loc           u:object_r:vendor_radio_prop:s0
 ro.radio.log_prefix        u:object_r:vendor_radio_prop:s0
+vendor.radio.sim_num.switch  u:object_r:vendor_radio_prop:s0
 
 # vendor_bluetooth_prop
 persist.vendor.bluetooth.a4wp           u:object_r:vendor_bluetooth_prop:s0