Documentation: kdump: fix minor typo

kdump.txt had a minor typo.
Signed-off-by: Cengiz Can <cengizc@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/kdump/kdump.txt

@@ -410,7 +410,7 @@ Notes on loading the dump-capture kernel:
 * Boot parameter "1" boots the dump-capture kernel into single-user
   mode without networking. If you want networking, use "3".
 
-* We generally don' have to bring up a SMP kernel just to capture the
+* We generally don't have to bring up a SMP kernel just to capture the
   dump. Hence generally it is useful either to build a UP dump-capture
   kernel or specify maxcpus=1 option while loading dump-capture kernel.
   Note, though maxcpus always works, you had better replace it with