Use BOARD_USES_VENDORIMAGE to detect vendor image presence - DO NOT MERGE

When building without vendor/... in the tree, we won't be creating a
vendorimage, so BOARD_VENDORIMAGE_FILE_SYSTEM_TYPE won't be defined. But
we still need to use the vendor image that will be present.

Bug: 31545062
Bug: 30040825
Change-Id: I756adc615aea11da60da4d3a4568caca9fed93ab
(cherry picked from commit 15366542057e7599d8514e9aee602d022c2ea14d)
2 files changed