[IA64] CONFIG_KEXEC/CONFIG_CRASH_DUMP permutations

Actually, on reflection I think that there is a good case for
keeping the options separate. I am thinking particularly of people
who want a very small crashdump kernel and thus don't want to compile
in kexec.

The patch below should fix things up so that all valid combinations of
KEXEC, CRASH_DUMP and VMCORE compile cleanly - VMCORE depends on
CRASH_DUMP which is why I said valid combinations. In a nutshell
it just untangles unrelated code and switches around a few defines.

Please note that it creats a new file, arch/ia64/kernel/crash_dump.c
This is in keeping with the i386 implementation.

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index 87c1c4f..a76add3 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -1239,7 +1239,7 @@
 	} else {
 		/* Dump buffered message to console */
 		ia64_mlogbuf_finish(1);
-#ifdef CONFIG_CRASH_DUMP
+#ifdef CONFIG_KEXEC
 		atomic_set(&kdump_in_progress, 1);
 		monarch_cpu = -1;
 #endif