[CHERIoT] Enable FeatureUnalignedScalarMem for cheriot.

This is a performance heuristic that signals that scalar unaligned
memory accesses are fast, i.e. not emulated.

Author: resistor

llvm/lib/Target/RISCV/RISCVProcessors.td

@@ -210,4 +210,5 @@ def CHERIOT : RISCVProcessorModel<"cheriot",
                                     FeatureCheri,
                                     FeatureCapMode,
                                     FeatureStdExtC,
-                                    FeatureStdExtM]>;
+                                    FeatureStdExtM,
+                                    FeatureUnalignedScalarMem]>;