Set separate system property to enable MTE settings toggle.

This is so other parts of the system can query whether the setting exists.

Bug: 244290023
Change-Id: I38a007231d6d779164ef5eff2a80d50fffe1085e

device-common.mk

diff --git a/device-common.mk b/device-common.mk
index 54b538c..447d674 100644
--- a/device-common.mk
+++ b/device-common.mk
@@ -48,4 +48,5 @@
 # force enable MTE.
 ifeq (,$(filter %_fullmte,$(TARGET_PRODUCT)))
 PRODUCT_PRODUCT_PROPERTIES += ro.arm64.memtag.bootctl_supported=1
+PRODUCT_PRODUCT_PROPERTIES += ro.arm64.memtag.bootctl_settings_toggle=1
 endif