dt-bindings: mmc: Add supports-cqe property

Add supports-cqe optional property for MMC hosts.

This property is used to identify the specific host controller
supporting command queue.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/mmc.txt

@@ -62,6 +62,8 @@ Optional properties:
   be referred to mmc-pwrseq-simple.txt. But now it's reused as a tunable delay
   waiting for I/O signalling and card power supply to be stable, regardless of
   whether pwrseq-simple is used. Default to 10ms if no available.
+- supports-cqe : The presence of this property indicates that the corresponding
+  MMC host controller supports HW command queue feature.
 
 *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line
 polarity properties, we have to fix the meaning of the "normal" and "inverted"