vendor: Enable one-handed mode

There's nothing device-specific about this feature, so enable it for
everyone.

Change-Id: I81e7a4595a9590f05a034c4b62263f45e0ea411f
diff --git a/config/common.mk b/config/common.mk
index 790b351..7efe9eb 100644
--- a/config/common.mk
+++ b/config/common.mk
@@ -19,6 +19,10 @@
 else
 # Enable ADB authentication
 PRODUCT_SYSTEM_DEFAULT_PROPERTIES += ro.adb.secure=1
+
+# Enable one-handed mode
+PRODUCT_PRODUCT_PROPERTIES += \
+    ro.support_one_handed_mode=true
 endif
 
 # Backup Tool