arm64: defconfig: enable further Rockchip platform drivers

arm64: defconfig: enable further Rockchip platform drivers

Enable the rockchip-dfi driver as a module, which is used on RK3588 as
well as RK3568 and RK3399 to measure memory bandwidth. For this, we also
enable PM_DEVFREQ_EVENT, which is a requirement for this driver.

Also enable the rockchip-rga driver as a module, which is used on
various Rockchip SoCs, including RK3588 and RK3399, to provide 2d
accelerated image transformations through a V4L2 interface.

Suggested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20250626-rk3588-defconfig-v2-1-ae6720964b01@collabora.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>