Fix misspellings of "system", "controller", "interrupt" and "necessary".

Fix the various misspellings of "system", controller", "interrupt" and
"[un]necessary".

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
diff --git a/include/linux/ipmi_smi.h b/include/linux/ipmi_smi.h
index efa292a..56ae438 100644
--- a/include/linux/ipmi_smi.h
+++ b/include/linux/ipmi_smi.h
@@ -118,7 +118,7 @@
 	/* Enable/disable firmware maintenance mode.  Note that this
 	   is *not* the modes defined, this is simply an on/off
 	   setting.  The message handler does the mode handling.  Note
-	   that this is called from interupt context, so it cannot
+	   that this is called from interrupt context, so it cannot
 	   block. */
 	void (*set_maintenance_mode)(void *send_info, int enable);