Use extended crashkernel command line on x86_64

This patch removes the crashkernel parsing from
arch/x86_64/kernel/machine_kexec.c and calls the generic function, introduced
in the last patch, in setup_bootmem_allocator().

This is necessary because the amount of System RAM must be known in this
function now because of the new syntax.

Signed-off-by: Bernhard Walle <bwalle@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/kernel/e820_64.c b/arch/x86/kernel/e820_64.c
index e422b81..5761686 100644
--- a/arch/x86/kernel/e820_64.c
+++ b/arch/x86/kernel/e820_64.c
@@ -226,7 +226,8 @@
 			request_resource(res, &code_resource);
 			request_resource(res, &data_resource);
 #ifdef CONFIG_KEXEC
-			request_resource(res, &crashk_res);
+			if (crashk_res.start != crashk_res.end)
+				request_resource(res, &crashk_res);
 #endif
 		}
 	}