arm: Refactor get_phys_addr FSR return mechanism

arm: Refactor get_phys_addr FSR return mechanism

Currently, the return code for get_phys_addr is overloaded for both
success/fail and FSR value return. This doesn't handle the case where
there is an error with a 0 FSR. This case exists in PMSAv7.

So rework get_phys_addr and friends to return a success/failure boolean
return code and populate the FSR via a caller provided uint32_t
pointer.

Signed-off-by: Peter Crosthwaite <[email protected]>
Message-id: a209e3d8ae00cda55260c970891f520210e26bad.1434066412[email protected]
Reviewed-by: Peter Maydell <[email protected]>
Signed-off-by: Peter Maydell <[email protected]>