ARM: OMAP: Fix relative includes for debug-devices.h

As discussed on linux-arm-kernel, we want to avoid
relative includes for the arch/arm/*omap* shared code:

http://www.spinics.net/lists/linux-omap/msg80520.html

Let's add plat/debug-devices.h for debug_card_init()
to fix the relative includes.

Note that drivers must not use this header as it will
break build for omap2+ CONFIG_MULTIPLATFORM builds.

Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/board-h4.c b/arch/arm/mach-omap2/board-h4.c
index bd11b0a..8668c72 100644
--- a/arch/arm/mach-omap2/board-h4.c
+++ b/arch/arm/mach-omap2/board-h4.c
@@ -33,7 +33,7 @@
 #include <asm/mach/map.h>
 
 #include <plat-omap/dma-omap.h>
-#include "debug-devices.h"
+#include <plat/debug-devices.h>
 
 #include <video/omapdss.h>
 #include <video/omap-panel-generic-dpi.h>