gcc-cross-canadian: Drop obsolete shlibs exclusion

This is a very old change as and be inferred from the name in the comment.
We've since had many changes to pkgdata including separating it
to its own sysroot now so the reasons for this blanket exclusion are
likely long gone.

If the shlib provides were really the problem I'd much rather have
a dedicated variable for that too.

Removing this fixes missing dependencies on nativesdk-libc and other
libs which would then happen automatically.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>