Document mmc-slot because used by amlogic,meson-mx-sdio.txt and
cavium-mmc.txt, so make it common.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
---
Changes in v2:
- Fixed description, limited to 3 slots
- Moved out mmc-slot in a separate common schema
- Link to v1: https://lore.kernel.org/r/20240911-topic-amlogic-arm32-upstream-bindings-fixes-convert-meson-mx-sdio-v1-1-b7bfae886211@linaro.org

---
Neil Armstrong (3):
      dt-bindings: mmc: controller: allow node name to be named slot@*
      dt-bindings: mmc: document mmc-slot
      dt-bindings: mmc: convert amlogic,meson-mx-sdio.txt to dtschema

 .../bindings/mmc/amlogic,meson-mx-sdio.txt         | 54 ------------
 .../bindings/mmc/amlogic,meson-mx-sdio.yaml        | 96 ++++++++++++++++++++++
 .../devicetree/bindings/mmc/mmc-controller.yaml    |  4 +-
 .../devicetree/bindings/mmc/mmc-slot.yaml          | 40 +++++++++
 4 files changed, 139 insertions(+), 55 deletions(-)
---
base-commit: 47ac09b91befbb6a235ab620c32af719f8208399
change-id: 20240911-topic-amlogic-arm32-upstream-bindings-fixes-convert-meson-mx-sdio-6fa70546ebb8

Best regards,
-- 
Neil Armstrong <neil.armstrong@linaro.org>