Commit 71c4443886ff ("fix(lib/rmm_el3_ifc): add console name to checksum
calculation") on TF-RMM updated the checksum calcualtion of the RMM
manifest to include the console names.
Include console names in the QEMU manifest to remain compatible with
RMM, just like commit aa99881d30 ("fix(rme): add console name to
checksum calculation") did for FVP.
Checksum calculation is done by adding together 64-bit values. Add a
helper that does this.
Change-Id: Ica6cab628160593830270bef1acdeb475d1c0c36
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>