mmc: sdhci-tegra: Add 8-bit support to device tree binding.

The previous patch which implemented a DT binding for sdhci-tegra did not
allow all platform data fields to be initialized from DT. The following
were missing:

is_8bit: Implemented by this patch.

pm_flags: Not implemented yet. There are no mainline users of this field.
  I'm not quite sure what it's for, and hence how to represent this
  in DT; the value ends up being assigned to host->mmc->pm_caps.

While we're at it, fix the binding documentation to refer to "SD/MMC"
instead of "eSDHC", since that's the correct name; "eSDHC" was cut/paste
from the Freescale binding docs.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

Documentation/devicetree/bindings/mmc/nvidia-sdhci.txt

@@ -5,13 +5,14 @@ and SDIO types of memory cards.
 
 Required properties:
 - compatible : Should be "nvidia,<chip>-sdhci"
-- reg : Should contain eSDHC registers location and length
-- interrupts : Should contain eSDHC interrupt
+- reg : Should contain SD/MMC registers location and length
+- interrupts : Should contain SD/MMC interrupt
 
 Optional properties:
 - cd-gpios : Specify GPIOs for card detection
 - wp-gpios : Specify GPIOs for write protection
 - power-gpios : Specify GPIOs for power control
+- support-8bit : Boolean, indicates if 8-bit mode should be used.
 
 Example:
 
@@ -22,4 +23,5 @@ sdhci@c8000200 {
 	cd-gpios = <&gpio 69 0>; /* gpio PI5 */
 	wp-gpios = <&gpio 57 0>; /* gpio PH1 */
 	power-gpios = <&gpio 155 0>; /* gpio PT3 */
+	support-8bit;
 };