treewide: Fix typo in Documentation/DocBook

This patch fix spelling typo in Documentation/DocBook.
It is because .html and .xml files are generated by make htmldocs,
I have to fix a typo within the source files.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/kernel/signal.c b/kernel/signal.c
index 940b30e..f481228 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2382,7 +2382,7 @@
  * @regs:		user register state
  * @stepping:		nonzero if debugger single-step or block-step in use
  *
- * This function should be called when a signal has succesfully been
+ * This function should be called when a signal has successfully been
  * delivered. It updates the blocked signals accordingly (@ka->sa.sa_mask
  * is always blocked, and the signal itself is blocked unless %SA_NODEFER
  * is set in @ka->sa.sa_flags.  Tracing is notified.