Ambiguity in ACL Documentation

In https://github.com/ARMmbed/uvisor/blob/master/docs/lib/API.md
`acl_list` is List of ACLs for the module

However, the the parameter is supposed to be ACLs for peripherals/IRQs

Open docs/lib/API.md and locate the acl_list parameter description. Confirm its meaning against the surrounding ACL API documentation, then clarify that it refers to ACLs for peripherals and IRQs rather than ACLs for the module. Done means the parameter description is unambiguous and consistent with the API.

Written by the indexing model from the issue text.