ram: rockchip: Fix Kconfig dependency for RAM_ROCKCHIP_DEBUG

There is no reason to show RAM_ROCKCHIP_DEBUG entry in other .config files
as I see it for Xilinx ZynqMP.

\# CONFIG_U_QE is not set
\# CONFIG_RAM is not set
CONFIG_RAM_ROCKCHIP_DEBUG=y

Add missing dependency on RAM_ROCKCHIP driver.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>