mod_scmi_perf: Fix invalid command return value
Created by: Sevenarth
According to the SCMIv2 spec section 4.1.4, if a command does not exist then SCMI_NOT_FOUND must be returned. This commit fixes this behaviour for the SCMI Performance Protocol.
Change-Id: I523ced9acf034ea4828c9b70096780ddc02e0ae5 Signed-off-by: Luca Vizzarro Luca.Vizzarro@arm.com