arm64: dts: rockchip: Enable onboard eMMC on Radxa E20C

arm64: dts: rockchip: Enable onboard eMMC on Radxa E20C

The Radxa E20C may come with an onboard eMMC (8GB / 16GB / 32GB / 64GB).

Enable support for the onboard eMMC on Radxa E20C.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Link: https://lore.kernel.org/r/20250305214108.1327208-4-jonas@kwiboo.se
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
[ upstream commit: 3a01b5f14a8ae2d45aea5aeed30001ac1655de86 ]

(cherry picked from commit bd4c8a1c08f92d863d89c0ddff59e5f5bc6a1e34)
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>