mtgc: Add no-op "lock" around SOA
mtgc: Add no-op "lock" around SOA

This adds no-op macros around the SOA which will actually do something
in the auto-mt GC mode.

Plasmaworks/Rogue,AbePralle/Rogue,Plasmaworks/Rogue,AbePralle/Rogue,Plasmaworks/Rogue,Plasmaworks/Rogue