product/rdn2: add SCP PIK register space declaration

SCP PIK includes registers for various system configuration and status.
SCP PIK is first one to come out of reset and it generates all the reset
conrols for SCP. Add the register space declaration for SCP PIK and the
subsequent base address from element management peripheral space.

Change-Id: Ic4c61d07875092d045b1e97b01b74811ffb1500b
Signed-off-by: Aditya Angadi <aditya.angadi@arm.com>