treewide: Fix typo in printk

Correct spelling typo in various part of drivers

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index 713d89f..422d9c3 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -38,7 +38,7 @@
 	MEI_DEV_STATE(POWER_DOWN);
 	MEI_DEV_STATE(POWER_UP);
 	default:
-		return "unkown";
+		return "unknown";
 	}
 #undef MEI_DEV_STATE
 }