Don't inherit userspace_reboot.mk from mainline_system.mk

Test: Checked that userspace_reboot.mk is included in device makefiles
Test: build
Bug: 135984674
Change-Id: If910e2a6baf8acaafc8bafdf8193ba7237f66f1a
Merged-In: If910e2a6baf8acaafc8bafdf8193ba7237f66f1a
(cherry picked from commit 0f38beca9433dbd5ced83d03d34da92063e3cd9d)
diff --git a/target/product/mainline_system.mk b/target/product/mainline_system.mk
index c880971..ccbc907 100644
--- a/target/product/mainline_system.mk
+++ b/target/product/mainline_system.mk
@@ -24,9 +24,6 @@
 # Enable updating of APEXes
 $(call inherit-product, $(SRC_TARGET_DIR)/product/updatable_apex.mk)
 
-# Mainline devices support userspace reboot
-$(call inherit-product, $(SRC_TARGET_DIR)/product/userspace_reboot.mk)
-
 # Shared java libs
 PRODUCT_PACKAGES += \
     com.android.nfc_extras \