classes/multilib: prevent multilib extension of nativesdk recipes
It isn't supported to mix multilib and nativesdk in the same target, so
explicitly skip multilib processing if nativesdk is inherited. As a
bonus this fixes a bunch of related "missing file" warnings from the
file checksum code during parsing because BPN was not correctly stripped
for these targets.
Second half of the fix for [YOCTO #3146].
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
