kernel-yocto: provide debug / summary information for metadata

It was mentioned that when developing a BSP, the information about what
definition was used, or what fragments have been applied is not obvious
and requires looking at the code.

With this change, we can trigger a full summary of the meta data gathering
phase when KCONF_AUDIT_LEVEL > 0.

Sample output follows:

   NOTE: do_kernel_metadata: for summary/debug, set KCONF_AUDIT_LEVEL > 0
   NOTE: kernel meta data summary for qemux86-64 (standard):
   NOTE:
   ======================================================================
   NOTE: BSP entry point / definition:
   /build/tmp/work/qemux86_64-poky-linux/linux-yocto/5.10.34+gitAUTOINC+bca3bfbc74_85c17ad073-r0/kernel-meta/bsp/common-pc-64/common-pc-64-standard.scc
   NOTE: Fragments from SRC_URI:
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/xt-checksum.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/ebtables.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/vswitch.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/lxc.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/docker.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/cgroup-hugetlb.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/xen.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/kubernetes.scc
   NOTE: KERNEL_FEATURES:  features/nfsd/nfsd-enable.scc
   features/debug/printk.scc features/kernel-sample/kernel-sample.scc
   features/netfilter/netfilter.scc cfg/virtio.scc
   features/drm-bochs/drm-bochs.scc cfg/sound.scc cfg/paravirt_kvm.scc
   features/scsi/scsi-debug.scc features/gpio/mockup.scc
   features/aufs/aufs-enable.scc cfg/fs/flash_fs.scc cfg/virtio.scc
   NOTE: Final scc/cfg list:
   /build/tmp/work/qemux86_64-poky-linux/linux-yocto/5.10.34+gitAUTOINC+bca3bfbc74_85c17ad073-r0/kernel-meta/bsp/common-pc-64/common-pc-64-standard.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/xt-checksum.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/ebtables.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/vswitch.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/lxc.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/docker.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/cgroup-hugetlb.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/xen.scc
   /poky/meta-virtualization/recipes-kernel/linux/linux-yocto/kubernetes.scc
   features/nfsd/nfsd-enable.scc features/debug/printk.scc
   features/kernel-sample/kernel-sample.scc
   features/netfilter/netfilter.scc cfg/virtio.scc
   features/drm-bochs/drm-bochs.scc cfg/sound.scc cfg/paravirt_kvm.scc
   features/scsi/scsi-debug.scc features/gpio/mockup.scc
   features/aufs/aufs-enable.scc cfg/fs/flash_fs.scc cfg/virtio.scc

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>