mm: docs: fix parameter names mismatch

There are several places where parameter descriptions do no match the
actual code.  Fix it.

Link: http://lkml.kernel.org/r/1516700871-22279-3-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 16424b9..f24c297 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -25,7 +25,7 @@
 /**
  * process_vm_rw_pages - read/write pages from task specified
  * @pages: array of pointers to pages we want to copy
- * @start_offset: offset in page to start copying from/to
+ * @offset: offset in page to start copying from/to
  * @len: number of bytes to copy
  * @iter: where to copy to/from locally
  * @vm_write: 0 means copy from, 1 means copy to