scmi_perf: Add initial unit tests
Created by: chuyue-luo-arm
Add unit tests for scmi_perf_protocol_version_handler(), scmi_perf_protocol_attributes_handler() and scmi_perf_protocol_message_attributes_handler().
Signed-off-by: Chuyue Luo Chuyue.Luo@arm.com Change-Id: I4c3f4139952889d2d3f71ba7261c3098e8d9879d