Fix OOPS in crash_kernel_shrink

[Vitaly Mayatskikh <v.mayatskih@gmail.com>]

Two "echo 0 > /sys/kernel/kexec_crash_size" OOPSes kernel. Also
content of this file is invalid after first shrink to zero: it shows 1
instead of 0.

This patch fixes it.

Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 87ebe8a..474a847 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1134,11 +1134,9 @@ int crash_shrink_memory(unsigned long new_size)
 
 	free_reserved_phys_range(end, crashk_res.end);
 
-	if (start == end) {
-		crashk_res.end = end;
+	if (start == end)
 		release_resource(&crashk_res);
-	} else
-		crashk_res.end = end - 1;
+	crashk_res.end = end - 1;
 
 unlock:
 	mutex_unlock(&kexec_mutex);

-- 
wbr, Vitaly