This patch adds a Kconfig variable, CONFIG_CRASH_DUMP, which configures the
built kernel for use as a Kdump kernel.

Currently "all" this involves is changing the value of KERNELBASE to 32 MB.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>