Previous changes in this series made the necessary driver additions and
updates. With those changes in-place we can add the platform.mk and
bl2_el3_setup.c to drive the boot process.

After this commit its possible to build a fully-functional TF-A for the
WaRP7 and boot from the BootROM to the Linux command prompt in secure or
non-secure mode.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>