[POWERPC] Find device-tree source file in default directory

If a .dts file is given to the bootwrapper script without a full path
name, look in a sensible place for it.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/boot/wrapper b/arch/powerpc/boot/wrapper
index 221b8c8..b8e4856 100755
--- a/arch/powerpc/boot/wrapper
+++ b/arch/powerpc/boot/wrapper
@@ -116,6 +116,9 @@
 done
 
 if [ -n "$dts" ]; then
+    if [ ! -r "$dts" -a -r "$object/dts/$dts" ]; then
+	dts="$object/dts/$dts"
+    fi
     if [ -z "$dtb" ]; then
 	dtb="$platform.dtb"
     fi