ARM: imx: Update spi_imx platform data to reflect current state

The docs for the spi_imx platform data still refer to a -32 offset used to
specify a native chip select.  This was removed in commit 602c8f4485cd
("spi: imx: fix use of native chip-selects with devicetree") and no
longer works as documented.  Update documentation.

The macro MXC_SPI_CS() is no longer is needed.

If a board uses all native chip selects, then it's not necessary to
specify a chip select array at all, as all native is the default (this is
how device-tree configured SPI masters work too).  Most of the spi-imx
platform data users have their chip select arrays removed by this patch.

This patch also fixes a bug in mx31moboard introduced in the '602 commit.
When that board was updated in commit 901f26bce64a ("ARM: imx: set
correct chip_select in platform setup") to reflect the SPI change, only
SPI bus 2 was updated and SPI bus 1 was left with non-sequential chip
selects.  The mc13783 spi device on bus 1 had its chip select updated as
if it were on bus 2.

CC: Sascha Hauer <kernel@pengutronix.de>
CC: Fabio Estevam <fabio.estevam@nxp.com>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Trent Piepho <tpiepho@impinj.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
diff --git a/arch/arm/mach-imx/mach-mx31lite.c b/arch/arm/mach-imx/mach-mx31lite.c
index a3250bc..a3cbba6 100644
--- a/arch/arm/mach-imx/mach-mx31lite.c
+++ b/arch/arm/mach-imx/mach-mx31lite.c
@@ -83,15 +83,8 @@ static const struct imxuart_platform_data uart_pdata __initconst = {
 };
 
 /* SPI */
-static int spi0_internal_chipselect[] = {
-	MXC_SPI_CS(0),
-	MXC_SPI_CS(1),
-	MXC_SPI_CS(2),
-};
-
 static const struct spi_imx_master spi0_pdata __initconst = {
-	.chipselect	= spi0_internal_chipselect,
-	.num_chipselect	= ARRAY_SIZE(spi0_internal_chipselect),
+	.num_chipselect	= 3,
 };
 
 static const struct mxc_nand_platform_data
@@ -133,13 +126,8 @@ static struct platform_device smsc911x_device = {
  * The MC13783 is the only hard-wired SPI device on the module.
  */
 
-static int spi1_internal_chipselect[] = {
-	MXC_SPI_CS(0),
-};
-
 static const struct spi_imx_master spi1_pdata __initconst = {
-	.chipselect	= spi1_internal_chipselect,
-	.num_chipselect	= ARRAY_SIZE(spi1_internal_chipselect),
+	.num_chipselect	= 1,
 };
 
 static struct mc13xxx_platform_data mc13783_pdata __initdata = {