The tricky of using BPN in a common inc file is rather hard to understand.
Simplfy this by moving it to the base vim recipe and use the standard
variable form.
(From OE-Core rev: cffa5930d86a464aceb4764eec510a2b8f5c44a1)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>