Add ro.boot.ddr_size sysprop to sepolicy

srcs/android/sysprop/MemoryProperties.sysprop

This property is populated by property service from the kernel
command line parameter androidboot.ddr_size=XXXX. Vendors can set
this command line option from the bootloader.

Bug: 231718727
Test: n/a
Change-Id: I3fb8a18125081b1a30dee715831f5701964cb375
diff --git a/private/property_contexts b/private/property_contexts
index f3ed5c7..56c7743 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -794,6 +794,7 @@
 ro.boot.bootloader         u:object_r:bootloader_prop:s0 exact string
 ro.boot.boottime           u:object_r:bootloader_prop:s0 exact string
 ro.boot.console            u:object_r:bootloader_prop:s0 exact string
+ro.boot.ddr_size           u:object_r:bootloader_prop:s0 exact string
 ro.boot.hardware           u:object_r:bootloader_prop:s0 exact string
 ro.boot.hardware.color     u:object_r:bootloader_prop:s0 exact string
 ro.boot.hardware.sku       u:object_r:bootloader_prop:s0 exact string