linux-yocto/*: restore branch designations

linux-yocto/*: restore branch designations

The fetcher now confirms that a given SRCREV exists on the branch specified
in the SRC_URI. The linux-yocto recipes used to do this themselves, but that
functionality was removed to allow builds when only the SRCREV was set and
to be similar to other recipes.

Now that the fetcher checks this value, and other recipes must also have
SRCREV + branch information, this extra information can be put back into
the recipes.

(From OE-Core rev: 4a562fd2614bb6ccce1222d47b9268d6980cf315)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>