Convert txt binding of TI's qspi controller (found on their omap SoCs) to
dtschema to allow for validation.

The changes, w.r.t. the original txt binding, are:

- Introduce "clocks" and "clock-names" which was never mentioned.
- Reflect that "ti,hwmods" is deprecated and is not a "required"
  property anymore.
- Introduce "num-cs" which allows for setting the number of chip
  selects.
- Drop "qspi_ctrlmod".
Signed-off-by: Kousik Sanagavarapu <five231003@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240501165203.13763-1-five231003@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>