only overriding misa.C

Author: Saad Khalid

dv/cosim/spike_cosim.cc

@@ -712,13 +712,10 @@ void SpikeCosim::fixup_csr(int csr_num, uint32_t csr_val) {
       break;
     }
     case CSR_MISA: {
-      // For Ibex, misa is hardwired,
-      // so applying mask to bits other then variable
-      // bits in different Ibex configs
+      // For Ibex, misa.C is hardwired
 
-      uint32_t misa_and_mask = 0x40901114;
-      uint32_t misa_or_mask = 0x100004;
-      reg_t new_val = (csr_val & misa_and_mask) | misa_or_mask;
+      uint32_t misa_or_mask = 0x4;
+      reg_t new_val = csr_val | misa_or_mask;
 #ifdef OLD_SPIKE
       processor->set_csr(csr_num, new_val);
 #else