ARM: davinci: create new common platform header for davinci

Remove individual platform header files for dm365, dm355, dm644x
and dm646x and consolidate it into a single and common
header file davinci.h placed in arch/arm/mach-davinci.

This reduces the pollution in the include/mach and is consistent
with Russell's suggestions as part of his "pet peaves" mail.
(See #4 in: http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/071516.html)

While at it, fix the forward declaration of spi_board_info,
and include the right header file instead.

The further patches in the series take  advantage of this consolidation
for easy implementation of IO_ADDRESS elimination.

Signed-off-by: Manjunath Hadli <manjunath.hadli@ti.com>
[nsekhar@ti.com: make davinci.h the first local include file,
fix forward declaration of spi_board_info and add back Deep Root
Systems, LLC copyright]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

arch/arm/mach-davinci/board-dm355-evm.c

@@ -26,13 +26,14 @@
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
 
-#include <mach/dm355.h>
 #include <mach/i2c.h>
 #include <mach/serial.h>
 #include <mach/nand.h>
 #include <mach/mmc.h>
 #include <mach/usb.h>
 
+#include "davinci.h"
+
 /* NOTE:  this is geared for the standard config, with a socketed
  * 2 GByte Micron NAND (MT29F16G08FAA) using 128KB sectors.  If you
  * swap chips, maybe with a different block size, partitioning may