kernel.bbclass: Add kernel_version_sanity_check function
The kernel being built should match what the recipe claims it is
building. This function ensures that happens by comparing the version
information in the kernel's Makefile to the PV the recipe is using.
v2 changes:
* Match against PV instead of LINUX_VERSION
* Match against EXTRAVERSION as well (e.g., -rc4)
* Cleaned up version string building
Fixes [YOCTO #6767].
Signed-off-by: California Sullivan <california.l.sullivan@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
