libmetal: Add default SRCREV to libmetal-dev.bb
libmetal: Add default SRCREV to libmetal-dev.bb

libmetal-dev.bb is supposed to always uses latest of master branch
if libmetal-dev is specified as preferred provider.

In order to allow no network mode, we add a default SRCREV not to
use auto if libmetal-dev is not specified as preferred provider.
So that we yocto pass all the recipes, it will not try to access
the network.

Signed-off-by: Wendy Liang <cac46fad14f88489ab4dbc3c1082c7dafae20187@xilinx.com>

OpenAMP/meta-openamp,OpenAMP/meta-openamp