[RISCV] Remove Group<m_riscv_Features_Group> from mcmodel_EQ_medlow/m…

…cmodel_EQ_medany. NFCI

As far as I can tell m_riscv_Features_Group is for options that
can be passed to cc1's -target-feature. These mcmodel aliases aren't
that.

I think they get treated as aliases and disappear before we get
to processing m_riscv_Features_Group so it didn't cause any problems.

I've left them in m_Group to match mcmodel_EQ.

clang/include/clang/Driver/Options.td

@@ -3543,10 +3543,10 @@ def msave_restore : Flag<["-"], "msave-restore">, Group<m_riscv_Features_Group>,
   HelpText<"Enable using library calls for save and restore">;
 def mno_save_restore : Flag<["-"], "mno-save-restore">, Group<m_riscv_Features_Group>,
   HelpText<"Disable using library calls for save and restore">;
-def mcmodel_EQ_medlow : Flag<["-"], "mcmodel=medlow">, Group<m_riscv_Features_Group>,
+def mcmodel_EQ_medlow : Flag<["-"], "mcmodel=medlow">, Group<m_Group>,
   Flags<[CC1Option]>, Alias<mcmodel_EQ>, AliasArgs<["small"]>,
   HelpText<"Equivalent to -mcmodel=small, compatible with RISC-V gcc.">;
-def mcmodel_EQ_medany : Flag<["-"], "mcmodel=medany">, Group<m_riscv_Features_Group>,
+def mcmodel_EQ_medany : Flag<["-"], "mcmodel=medany">, Group<m_Group>,
   Flags<[CC1Option]>, Alias<mcmodel_EQ>, AliasArgs<["medium"]>,
   HelpText<"Equivalent to -mcmodel=medium, compatible with RISC-V gcc.">;
 def menable_experimental_extensions : Flag<["-"], "menable-experimental-extensions">, Group<m_Group>,