dt-bindings: mmc: sdhci-of-dwcmhsc: Allow use of a power-domain

dt-bindings: mmc: sdhci-of-dwcmhsc: Allow use of a power-domain

The commit 7e856617a1f3 ("dt-bindings: mmc: Add support for rk3576
eMMC") limited use of power-domains to Rockchip RK3576.

Remove the power-domains: false to allow use of power-domains with more
controllers, e.g. with SDHCI on Rockchip RK3528.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250518220707.669515-6-jonas@kwiboo.se
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>