Sort the SPI makefile and enforce the naming convention spi_*.c for
spi drivers.

This change also rolls the contents of atmel_spi.h into the .c file
since there is only one user of that particular include file.

v2: - Use 'spi-' prefix instead of 'spi_' to match what seems to be
      be the predominant pattern for subsystem prefixes.
    - Clean up filenames in Kconfig and header comment blocks
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>

include/linux/dw_spi.h only includes driver internal data.  It doesn't
expose a platform_data configuration structure or similar (at least
nothing in-tree).  This patch moves the header into drivers/spi so
that the scope is limited to only the dw_spi_*.c driver files
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Cc: Feng Tang <feng.tang@intel.com>
Cc: spi-devel-general@lists.sourceforge.net

dw_spi driver in upstream only supports PIO mode, and this patch
will support it to cowork with the Designware dma controller used
on Intel Moorestown platform, at the same time it provides a general
framework to support dw_spi core to cowork with dma controllers on
other platforms

It has been tested with a Option GTM501L 3G modem and Infenion 60x60
modem. To use DMA mode, DMA controller 2 of Moorestown has to be enabled

Also change the dma interface suggested by Linus Walleij.
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NFeng Tang <feng.tang@intel.com>
[Typo fix and renames to match intel_mid_dma renaming]
Signed-off-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>