Remove unnecessary double-setting of mstatus.FS=Dirty

fflags->write() already sets that.

riscv/decode.h

@@ -280,7 +280,6 @@ private:
 #define require_vm do { if (insn.v_vm() == 0) require(insn.rd() != 0);} while(0);
 
 #define set_fp_exceptions ({ if (softfloat_exceptionFlags) { \
-                               dirty_fp_state; \
                                STATE.fflags->write(STATE.fflags->read() | softfloat_exceptionFlags); \
                              } \
                              softfloat_exceptionFlags = 0; })

riscv/processor.cc

@@ -978,7 +978,6 @@ void processor_t::set_csr(int which, reg_t val)
       es.set_sentropy(val);
       break;
     case CSR_FCSR:
-      dirty_fp_state;
       state.fflags->write((val & FSR_AEXC) >> FSR_AEXC_SHIFT);
       state.frm->write((val & FSR_RD) >> FSR_RD_SHIFT);
       break;