vim: split the common part into vim.inc

vim: split the common part into vim.inc

Previously vim-tiny would include the vim recipe wholesale;
this meant that they had to be upgraded in a single transaction
which devtool cannot cope with. This thwarted the latest AUH
run in particular.

Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>