dt-bindings: mmc: Remove bindings for Intel Thunder Bay SoC"

Remove Thunder Bay specific code as the product got cancelled
and there are no end customers or users.

Signed-off-by: A, Rashmi <rashmi.a@intel.com>
Reviewed-by: Hunter, Adrian <adrian.hunter@intel.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230316120549.21486-3-rashmi.a@intel.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>