arm-bsp-extras/scp-firmware: Add SCP handshake and CMN config

Introduce new patches for fvp-rd-aspen to:
 * Configure the ATU (managed for now)
 * Configure the CMN
 * Perform the RSE<->SI0 handshake
 * Configure the PPUs and power domains

For now, all clock and timer configuration is omitted.

Bump the SHA to a more recent version, which includes the PPU "AE"
additions.

Signed-off-by: Peter Hoyes <peter.hoyes@arm.com>