Unfortunately when enabling FDT fixups for the AM62x family of SoCs and
moving TF-A to the bottom of RAM we missed the BeaglePlay. This is
causing Linux's memory allocator to clobber TF-A and break its boot.

Enable OF_SYSTEM_SETUP to fixup the kernel's FDT to inform it of the
actual location of the firmware

CC: Andrew Davis <afd@ti.com>
CC: Nishanth Menon <nm@ti.com>
CC: Robert Nelson <robertcnelson@gmail.com>
Reported-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Bryan Brattlof <bb@ti.com>