hw/sd/omap_mmc: Use similar API for "wire up omap_clk" to other OMAP devices

hw/sd/omap_mmc: Use similar API for "wire up omap_clk" to other OMAP devices

The approach we've settled on for handling the omap_clk wiring for
OMAP devices converted to QDev is to have a function omap_foo_set_clk()
whose implementation just sets the field directly in the device's
state struct. (See the "TODO" comment near the top of omap.h.)
Make omap_mmc do the same.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20250128104519.3981448-6-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>