kernel-yocto: relax BSP definition test
commit
44aea7b873 [kernel-yocto: ensure that only valid BSPs are built]
introduced a new check to ensure that a valid BSP definition was found,
rather than building something that 'closely' matched the current
MACHINE.
This check breaks valid configurations which do not have a bsp
definition but are otherwise completely configured machines.
To allow both elements to co-exist (and not add warnings or errors
to otherwise valid builds), we first check to see if an empty bsp
definition was found, but then check to see if a defconfig was
provided.
If a defconfig has been provided, that is a sign that the board
configuration is complete and we should continue the build without
otherwise bothering the user.
Tested on meta-raspberrypi and linux-yocto*
Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
