Modify INTERNAL_KERNEL_CMDLINE instead of BOARD_ variant

The current modification of the variable within the build system
prohibits making the variable readonly.

Test: build_test
Test: boot blueline
Change-Id: Iec6058a163b5951db389d4adc0d9d0397431efb1
diff --git a/core/Makefile b/core/Makefile
index 3cc9831..9a2d985 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -930,7 +930,7 @@
 endif
 endif
 
-INTERNAL_KERNEL_CMDLINE := $(strip $(BOARD_KERNEL_CMDLINE) buildvariant=$(TARGET_BUILD_VARIANT) $(VERITY_KEYID))
+INTERNAL_KERNEL_CMDLINE := $(strip $(INTERNAL_KERNEL_CMDLINE) buildvariant=$(TARGET_BUILD_VARIANT) $(VERITY_KEYID))
 ifdef INTERNAL_KERNEL_CMDLINE
 INTERNAL_BOOTIMAGE_ARGS += --cmdline "$(INTERNAL_KERNEL_CMDLINE)"
 endif
@@ -1021,7 +1021,6 @@
 endif
 $(eval $(call copy-one-file,$(BOARD_PREBUILT_BOOTIMAGE),$(INSTALLED_BOOTIMAGE_TARGET)))
 else # BOARD_PREBUILT_BOOTIMAGE not defined
-INTERNAL_KERNEL_CMDLINE := $(strip $(BOARD_KERNEL_CMDLINE))
 INSTALLED_BOOTIMAGE_TARGET :=
 endif # BOARD_PREBUILT_BOOTIMAGE
 endif # TARGET_NO_KERNEL
diff --git a/core/board_config.mk b/core/board_config.mk
index fecb6f6..1e0e9e1 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -82,6 +82,7 @@
 BOARD_KERNEL_BASE := $(strip $(BOARD_KERNEL_BASE))
 BOARD_KERNEL_PAGESIZE := $(strip $(BOARD_KERNEL_PAGESIZE))
 
+INTERNAL_KERNEL_CMDLINE := $(strip $(BOARD_KERNEL_CMDLINE))
 
 ifeq ($(TARGET_CPU_ABI),)
   $(error No TARGET_CPU_ABI defined by board config: $(board_config_mk))
diff --git a/core/config.mk b/core/config.mk
index e0bfe75..d4069d3 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -979,7 +979,7 @@
 endif
 
 # The metadata device must be supplied to init via the kernel command-line.
-BOARD_KERNEL_CMDLINE += androidboot.super_partition=$(BOARD_SUPER_PARTITION_METADATA_DEVICE)
+INTERNAL_KERNEL_CMDLINE += androidboot.super_partition=$(BOARD_SUPER_PARTITION_METADATA_DEVICE)
 
 BOARD_BUILD_RETROFIT_DYNAMIC_PARTITIONS_OTA_PACKAGE := true
 
@@ -1013,7 +1013,7 @@
 endif
 
 ifneq ($(BOARD_SUPER_PARTITION_METADATA_DEVICE),super)
-BOARD_KERNEL_CMDLINE += androidboot.super_partition=$(BOARD_SUPER_PARTITION_METADATA_DEVICE)
+INTERNAL_KERNEL_CMDLINE += androidboot.super_partition=$(BOARD_SUPER_PARTITION_METADATA_DEVICE)
 endif
 BOARD_BUILD_RETROFIT_DYNAMIC_PARTITIONS_OTA_PACKAGE :=