Remove slpi from persist.vendor.sys.ssr.restart_level

slpi isn't independent subsystem on sm7250

Bug: 171772275
Change-Id: I68b55f604ef8a18ceb8ac4dd910d2eebe33e47e9
diff --git a/device-common.mk b/device-common.mk
index 2d08848..1fdb7bd 100644
--- a/device-common.mk
+++ b/device-common.mk
@@ -647,7 +647,7 @@
 
 # Subsystem silent restart
 PRODUCT_PROPERTY_OVERRIDES += \
-    persist.vendor.sys.ssr.restart_level=modem,adsp,slpi
+    persist.vendor.sys.ssr.restart_level=modem,adsp
 
 ifneq (,$(filter userdebug eng, $(TARGET_BUILD_VARIANT)))
 # Sensor debug flag