The signature and naming of the Montgomrey initialisation function in
development and in the LTS was different. Align them for easier
readability and maintenance.
Signed-off-by: Janos Follath <janos.follath@arm.com>
So far we needed it only locally here, but we will need calculating RR
for safe unblinding in RSA as well.
Signed-off-by: Janos Follath <janos.follath@arm.com>