Prevent RIL from powering down SIM when modem is in low power mode

b/7140010

When telephony sends RADIO_POWER request, RIL will not power down the
SIM card when persist.radio.apm_sim_not_pwdn property is set to 1.

Change-Id: I9a225d36e9c9bfd6262e9c0593e61674aaeb1c72
Signed-off-by: Iliyan Malchev <malchev@google.com>
diff --git a/device.mk b/device.mk
index 64ac561..7b211f4 100644
--- a/device.mk
+++ b/device.mk
@@ -145,6 +145,10 @@
 	persist.audio.fluence.mode=endfire \
 	persist.audio.lowlatency.rec=false
 
+# Do not power down SIM card when modem is sent to Low Power Mode.
+PRODUCT_PROPERTY_OVERRIDES += \
+	persist.radio.apm_sim_not_pwdn=1
+
 #Upto 3 layers can go through overlays
 PRODUCT_PROPERTY_OVERRIDES += debug.mdpcomp.maxlayer=3