TBBR authentication framework depends on the plat_get_rotpk_info()
function to return the pointer to the Root of Trust Public Key (ROTPK)
stored in the platform along with its length. Add this function for
RD-Daniel platform to support Trusted Board Boot. The function makes use
of the wrapper function provided by the arm common trusted board boot
function to get the ROTPK hash.

Change-Id: I6c2826a7898664afea19fd62432684cfddd9319a
Signed-off-by: Vijayenthiran Subramaniam <vijayenthiran.subramaniam@arm.com>