Specify --ramdisk_name for vendor ramdisks for vendor_boot v4

When building vendor_boot v4 with multiple vendor ramdisks, pass the
name of each ramdisk to mkbootimg.

Bug: 177882072
Test: Modify a device BoardConfig and verify the built vendor_boot.img
  with unpack_bootimg
Change-Id: I679d277aa88f1e10678d2f74b579e4140536e267
diff --git a/core/Makefile b/core/Makefile
index 40e9274..20a8a88 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1027,6 +1027,9 @@
     $(eval vendor_ramdisk_fragment_target := $(call build-vendor-ramdisk-fragment,$(vendor_ramdisk_fragment))) \
     $(if $(filter --ramdisk_type,$(BOARD_VENDOR_RAMDISK_FRAGMENT.$(vendor_ramdisk_fragment).MKBOOTIMG_ARGS)),, \
       $(eval BOARD_VENDOR_RAMDISK_FRAGMENT.$(vendor_ramdisk_fragment).MKBOOTIMG_ARGS += --ramdisk_type DLKM))) \
+  $(if $(filter --ramdisk_name,$(BOARD_VENDOR_RAMDISK_FRAGMENT.$(vendor_ramdisk_fragment).MKBOOTIMG_ARGS)), \
+    $(error Must not specify --ramdisk_name for vendor ramdisk fragment: $(vendor_ramdisk_fragment))) \
+  $(eval BOARD_VENDOR_RAMDISK_FRAGMENT.$(vendor_ramdisk_fragment).MKBOOTIMG_ARGS += --ramdisk_name $(vendor_ramdisk_fragment)) \
   $(eval INTERNAL_VENDOR_RAMDISK_FRAGMENT_TARGETS += $(vendor_ramdisk_fragment_target)) \
   $(eval INTERNAL_VENDOR_RAMDISK_FRAGMENT_ARGS += $(BOARD_VENDOR_RAMDISK_FRAGMENT.$(vendor_ramdisk_fragment).MKBOOTIMG_ARGS) --vendor_ramdisk_fragment $(vendor_ramdisk_fragment_target)) \
 )