Rename vendor-ramdisk to vendor_ramdisk

Rename to get consistent ramdisk directory naming in
out/target/product/<name>:
  debug_ramdisk
  ramdisk
  vendor_debug_ramdisk
  vendor_ramdisk

Test: build and inspect out/target/product/<name>
Change-Id: I81d8f2cafe5e1b9024196cd74772b78d4a4aec58
diff --git a/core/envsetup.mk b/core/envsetup.mk
index 33f4f25..8c25086 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -275,7 +275,7 @@
 _vendor_dlkm_path_placeholder := ||VENDOR_DLKM-PATH-PH||
 _odm_dlkm_path_placeholder := ||ODM_DLKM-PATH-PH||
 TARGET_COPY_OUT_VENDOR := $(_vendor_path_placeholder)
-TARGET_COPY_OUT_VENDOR_RAMDISK := vendor-ramdisk
+TARGET_COPY_OUT_VENDOR_RAMDISK := vendor_ramdisk
 TARGET_COPY_OUT_PRODUCT := $(_product_path_placeholder)
 # TODO(b/135957588) TARGET_COPY_OUT_PRODUCT_SERVICES will copy the target to
 # product