DM355/DM365/DM6467 and DA8xx).  Mostly the same as the patch by Sandeep
Paulraj.

This has been tested on the DM6446 by defining a spidev device and using a
scope (to check correctness) and a hardware loopback.

This was NOT tested on DM355, DM365 and DM6467 - in fact, it will probably
not work "as is" because its default mode is CS low-inactive (default mode
of SPI in kernel) - need to set CS_HIGH mode to work as in the previous
patch.

Changes from the patch by Sandeep Paulraj:

Bug fixes:
 * Additional word written with chip select up after each transfer.
   Particulary problematic with NO_CS mode where this word can't be
   distiguished from correct words. Problem was in davinci_chip_select.
 * setup() for one chip select may interfere with transfer for another
 * Small nitpicks (bits that can be changed only on VERSION_2)

Features added:
 * Support DM6446
 * Support CS_HIGH mode (using SPIDEF register). Note that CS low is default.

Other:
 * Less accesses to registers used.
 * Once-per-device configuration is done only in probe(), not each transfer.

Uglyness still there:
 * VERSION_X definitions for different SPI controllers - added VERSION_3
   for the dm6446, which is ugly.

NOTE:
This patch is based on following patches:

SPI: DaVinci: Adding SPI driver for DM3xx/DM6467/DA8xx

 The patch adds support for SPI in DaVinci
 DM355/DM365/DM6467 and DA8xx.

 This has been tested on the DM355, DM365 and DM6467 EVMs using
 the EEPROM connected to SPI0
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>

DaVinci: DM646x: Adding Support for SPI

 The patch does the following

 1) Adds a clock for SPI
 2) Defines resources specific to DM646x SOC
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Pablo Bitton <pablo.bitton@gmail.com>
Cc: Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>