fastboot: support vbmeta_vendor.img

Bug: 181909612
Bug: 190564127
Test: build
Change-Id: If61fff1c83513d71605c0cef2737a38f7575d69b
Merged-In: If61fff1c83513d71605c0cef2737a38f7575d69b
(cherry picked from commit a48a78356fa59c94e61482ab5bc39532530bac58)
1 file changed