configs: rpi_4 : enable SDHCI_SDMA config

Enable SDHCI_SDMA configuration.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Minkyu Kang <mk7.kang@samsung.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>