Add missing vendor_kernel_ramdisk dependency to target-files.zip

The rule that builds target-files.zip has no dependency on the
vendor_kernel_ramdisk image, which means the files in that image
may not be in place when target-filse.zip is built, causing a
build error:
mkbootfs: cannot open directory '/mnt/disks/build-disk/src/googleplex-android/aosp-main-future-without-vendor/out/target/product/cheetah/obj/PACKAGING/target_files_intermediates/aosp_cheetah-target_files/VENDOR_KERNEL_BOOT/RAMDISK': No such file or directory

Add the missing dependency.

Bug: 365887100
Test: none
Flag: EXEMPT bugfix
Change-Id: I5cdec9bbb35970e4d5e27a6b10ad118ce11835a9
diff --git a/core/Makefile b/core/Makefile
index bf2d48a..306bb7a 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -6462,6 +6462,7 @@
 	    $(INSTALLED_RAMDISK_TARGET) \
 	    $(INSTALLED_DTBIMAGE_TARGET) \
 	    $(INSTALLED_2NDBOOTLOADER_TARGET) \
+	    $(INSTALLED_VENDOR_KERNEL_RAMDISK_TARGET) \
 	    $(BUILT_RAMDISK_16K_TARGET) \
 	    $(BUILT_KERNEL_16K_TARGET) \
 	    $(BOARD_PREBUILT_DTBOIMAGE) \