checkvintf: Add --check-one option.

checkvintf --check-one can check consistency of VINTF files within
a single partition. Currently, only system and vendor is supported
(because product / odm / system_ext VINTF files cannot be retrieved
independently).

Test: checkvintf --check-one /system:$OUT/system
Test: checkvintf --check-one /vendor:$OUT/vendor
Test: m check-vintf-all

Change-Id: Ibb396ee9b2292877c95e4ed8b636a9005d400475
1 file changed