Merge changes from topic "brcm_rng_driver" into integration

* changes:
driver: brcm: add RNG driver
plat/brcm: Define RNG base address

driver: brcm: add RNG driver

Signed-off-by: Bharat Gooty <bharat.gooty@broadcom.com>
Change-Id: I490d7e4d49bd9f5a62d343a264a1e14c2066ceca