[PATCH] powerpc: Export htab start/end via device tree

The userspace kexec-tools need to know the location of the htab on non-lpar
machines, as well as the end of the kernel. Export via the device tree.

NB. This patch has been updated to use "linux,x" property names. You may
need to update your kexec-tools to match.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>