rockchip: firefly-rk3399: enable SPL_ATF_NO_PLATFORM_PARAM

The Rockchip-released ATF for the Firefly apparently (i.e. Kever
reported this) does not tolerate a FDT being passed as the platform
parameter and will run into a hard stop.

To work around this limitation in the ATF parameter handling, we
enable SPL_ATF_NO_PLATFORM_PARAM (which will force passing NULL for
the platform parameters).

Note that this only affects this platform, as the ATF releases for the
RK3368 and RK3399 have always either ignored the platform parameter
(i.e. before the FDT-based parameters were supported) or support
receiving a pointer to a FDT.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>