Append a node to hw-config dtb which will include a property to hold
the value of the SSC_VERSION register. This will be used by the BL33
stage to determine the platform-id and the config-id of the platform
it is executing on.

Change-Id: Ie7b1e5d8c1bbe0efdb7ef0714f14b7794ec6058e
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>