Do Arm offer A53 with only MPU? Because right now we have only one to one mapping. we just need to use MPU only. Yes I understand MMU is superset of MPU but can be expensive (performance wise). Or there other way to use MMU?
The Cortex-A53 is only available with a MMU, there isn't an option to have it with an MPU instead. You will need to have a translation table, even if all the mappings are flat mapped.
From memory, the only Arm processor that could have both was the ARM1026EJ-S (which is going back a long time).