platform/rdfremont: enable bl1 based boot flow

TF-A support booting from BL1 instead of BL31. With this flow, BL2 would
be loading the required images. Hence pre-loading of BL31, NT FW config
BL33 and RMM images are not required.

Signed-off-by: Sathyam Panda <sathyam.panda@arm.com>
Change-Id: Id0eb349989c962499f6f00a2f227b6a4fe4a0050