yocto-bsp: Fix git url parsing, allowing for local mirrors

yocto-bsp: Fix git url parsing, allowing for local mirrors

The git URLs used in bitbake recipes are not compatible directly with git.  In
bitbake-speak, all git URLs start with git:// and the protocol is optionally
specified in the SRC_URI. Local git mirrors are specified like so:

    git:///path/to/local/mirror.git;protocol=file

The URL that git requires would be:

    file:///path/to/local/mirror.git

Update the yocto-bsp kernel.py to make the necessary adjustment when parsing
the SRC_URI to extract the git URL.

(From meta-yocto rev: 30506f51cc95f0994cf54144295832e931d15f61)

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tom Zanussi <tom.zanussi@intel.com>
CC: evadeflow@gmail.com
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>