BL1: Upgrade pyhsslms version

Regenerate keys, as disk storage format has changed. Soft-pin version in
requirements.txt to prevent builds failing if new versions are released.

Change-Id: I27318ebd1df2c9b7adbc5dc7bfb736d27f095815
Signed-off-by: Raef Coles <raef.coles@arm.com>
4 files changed