mkvendor.sh: force armeabi-v7a

Change-Id: I9f29eec73a13144b47ff7b1db1d59cb1e5a4ef64
mkvendor.sh: typo

Change-Id: I8cc2303fde7c815384e09f65b6d4a1116ac29ee4
mkvendor.sh: more fixes

Change-Id: I0c641d42a96e44bb9170475d5de21cb8644e4d3d