Masari/MSR limited support
Unlike other cryptonight algorithms in Masari variant changed iterations count, with limitations of OpenCL platform it means:

* Miner not able switch in runtime between `cn/msr` and all other `cn/*` algorithms.
* Miner not able switch in runtime to `cn/msr` from other `cn/*` algorithms.
* `cn/msr` should set only via global `algo` option.

These restrictions only applied to OpenCL/AMD miner, CPU miner can switch between all cryptonight variants.