MFH: r543571

net/freerdp: update to security/bugfix release 2.2.0

This update primarily fixes CVE-2020-15103. See the full changelog for
other bugfixes that were included:

https://github.com/FreeRDP/FreeRDP/releases/tag/2.2.0

PR: 248198
Submitted by: VVD <vvd unislabs com>
Security: a955cdb7-d089-11ea-8c6f-080027eedc6a

Approved by: ports-secteam (joneum)