mrsas: remove additional MPT command allocation for R1 FP command

There is an additional MPT command allocation for R1 fp command which
will lead to MPT command unavailablity in case of rigorous R1 FP IOs.

Remove additional MPT command allocation for R1 FP.

Reviewed by: imp
PR: 261377

(cherry picked from commit 241bb95552a39d440519162b544c776adcb7cf57)