memory-hotplug.rst: fix two instances of "movablecore" that should be "movable_node"

Patch series "memory-hotplug.rst: document the "auto-movable" online
policy".

Now that the memory-hotplug.rst overhaul is upstream, proper
documentation for the "auto-movable" online policy, documenting all new
toggles and options.  Along, two fixes for the original overhaul.

This patch (of 3):

We really want to refer to the "movable_node" kernel command line
parameter here.

Link: https://lkml.kernel.org/r/20210930144117.23641-2-david@redhat.com
Fixes: ac3332c4 ("memory-hotplug.rst: complete admin-guide overhaul")
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/admin-guide/mm/memory-hotplug.rst

@@ -166,7 +166,7 @@ Or alternatively::
 	% echo 1 > /sys/devices/system/memory/memoryXXX/online
 
 The kernel will select the target zone automatically, usually defaulting to
-``ZONE_NORMAL`` unless ``movablecore=1`` has been specified on the kernel
+``ZONE_NORMAL`` unless ``movable_node`` has been specified on the kernel
 command line or if the memory block would intersect the ZONE_MOVABLE already.
 
 One can explicitly request to associate an offline memory block with
@@ -393,7 +393,7 @@ command line parameters are relevant:
 ======================== =======================================================
 ``memhp_default_state``	 configure auto-onlining by essentially setting
                          ``/sys/devices/system/memory/auto_online_blocks``.
-``movablecore``		 configure automatic zone selection of the kernel. When
+``movable_node``	 configure automatic zone selection in the kernel. When
 			 set, the kernel will default to ZONE_MOVABLE, unless
 			 other zones can be kept contiguous.
 ======================== =======================================================