hw/sd/omap_mmc: Convert to SDBus API

hw/sd/omap_mmc: Convert to SDBus API

Convert the OMAP MMC controller to the new SDBus API:
 * the controller creates an SDBus bus
 * instead of sd_foo functions on the SDState object, call
   sdbus_foo functions on the SDBus
 * the board code creates a proper TYPE_SD_CARD object and attaches
   it to the controller's SDBus, instead of the controller creating
   a card directly via sd_init() that never gets attached to any bus
 * because the SD card object is on a bus, it gets reset automatically
   by the "traverse the qbus tree resetting things" code, and we don't
   need to manually reset the card from the controller reset function

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20250128104519.3981448-5-peter.maydell@linaro.org>
[PMD: Include "hw/sd/sd.h" instead of "hw/sd/sdcard_legacy.h",
      create bus in omap_mmc_initfn() instead of omap_mmc_realize()]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>