Provided more details in the explanation and fixed a link to the
section on using virtual providers.
(From yocto-docs rev: ace74e24f001b83c9177266b0a6f15ce96dd04b0)
Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>