Fix references to the documentation files

Many boot image configuration files refer to the
appropriate documentation file, but these references
contain typos in the directory and file name. Fix
them. Also fix reference to doc/README.SPL file.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Prafulla Wadaskar <prafulla@marvell.com>
Cc: Stefano Babic <sbabic@denx.de>
Acked-by: Stefano Babic <sbabic@denx.de>
diff --git a/board/d-link/dns325/kwbimage.cfg b/board/d-link/dns325/kwbimage.cfg
index 97cb090..6df7939 100644
--- a/board/d-link/dns325/kwbimage.cfg
+++ b/board/d-link/dns325/kwbimage.cfg
@@ -25,7 +25,7 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 # MA 02110-1301 USA
 #
-# Refer docs/README.kwimage for more details about how-to configure
+# Refer doc/README.kwbimage for more details about how-to configure
 # and create kirkwood boot image
 #