multi boot.img support cleanups

The kernel should not be specified in INTERNAL_RECOVERYIMAGE_ARGS, since
it is already given to mkbootimg directly.

The MKBOOTIMG_KERNEL_ARG macro is unused.

Bug: 151094943
Change-Id: Ie16a7bf7d77c0436d933abbb02c6dcb9202d5fe7
diff --git a/core/Makefile b/core/Makefile
index 8e22ff6..5b3c4c9 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -2122,8 +2122,7 @@
 	$(call append-recovery-ui-properties,$(PRIVATE_RECOVERY_UI_PROPERTIES),$@)
 
 ifeq (truetrue,$(strip $(BUILDING_VENDOR_BOOT_IMAGE))$(strip $(AB_OTA_UPDATER)))
-  INTERNAL_RECOVERYIMAGE_ARGS := \
-      --kernel $(recovery_kernel) --ramdisk $(recovery_ramdisk)
+  INTERNAL_RECOVERYIMAGE_ARGS := --ramdisk $(recovery_ramdisk)
 ifdef GENERIC_KERNEL_CMDLINE
   INTERNAL_RECOVERYIMAGE_ARGS += --cmdline "$(GENERIC_KERNEL_CMDLINE)"
 endif
@@ -2200,10 +2199,10 @@
 # $(2): kernel file
 define build-recoveryimage-target
   $(if $(filter true,$(PRODUCT_SUPPORTS_VBOOT)), \
-    $(MKBOOTIMG) --kernel $(2) $(MKBOOTIMG_KERNEL_ARG) $(INTERNAL_RECOVERYIMAGE_ARGS) \
+    $(MKBOOTIMG) --kernel $(2) $(INTERNAL_RECOVERYIMAGE_ARGS) \
                  $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_RECOVERY_MKBOOTIMG_ARGS) \
                  --output $(1).unsigned, \
-    $(MKBOOTIMG) --kernel $(2) $(MKBOOTIMG_KERNEL_ARG) $(INTERNAL_RECOVERYIMAGE_ARGS) \
+    $(MKBOOTIMG) --kernel $(2) $(INTERNAL_RECOVERYIMAGE_ARGS) \
                  $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_RECOVERY_MKBOOTIMG_ARGS) \
                  --output $(1))
   $(if $(filter true,$(PRODUCT_SUPPORTS_BOOT_SIGNER)),\