u-boot: Split do_configure logic into separate file
Some auxiliary u-boot recipes may need u-boot properly configured
(including *.cfg additions via bbappends) but aren't necessarily
building u-boot itself; to support such situations, here we split the
u-boot do_configure() out of u-boot.inc and into its own
u-boot-configure.inc.
Signed-off-by: Zev Weiss <zev@bewilderbeest.net> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
