[TF-M] Deprecation of platform MPS2/SSE-200_AWS

Hi Everyone,

I would like to propose the deprecation of platform MPS2/SSE-200_AWS because the platform is no longer available to use: https://aws.amazon.com/marketplace/pp/ARM-Ltd-DesignStart-FPGA-on-Cloud-Cort... As per the process, this proposal is open for discussion for a period of 4 weeks and if there are no major objections, the platform should be marked as deprecated and removed from TF-M master after next release.

Thanks and Best regards, Marton Berke