ARM: smp: Revert recent SMP update

Revert "ARM: SoC: convert MSM to SMP operations"
Revert "ARM: smp: remove wrapper functions"
Revert "ARM: smp: Make SMP operations mandatory"

There are no functional advantages that justify diverging from caf branches.

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>