fix file specification in comments

Many files include the filename at the beginning, serveral used a wrong one.

Signed-off-by: Uwe Zeisberger <Uwe_Zeisberger@digi.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/include/asm-xtensa/dma-mapping.h b/include/asm-xtensa/dma-mapping.h
index c425f10..c39c91d 100644
--- a/include/asm-xtensa/dma-mapping.h
+++ b/include/asm-xtensa/dma-mapping.h
@@ -1,5 +1,5 @@
 /*
- * include/asm-xtensa/dma_mapping.h
+ * include/asm-xtensa/dma-mapping.h
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive