Remove debug memory access check

This check does not make sense for our cosimulation environment (the
spike debug module is not in use) and leads to false failures when
randomly generated programs want to access the spike debug memory
address range.

riscv/mmu.cc

@@ -116,10 +116,6 @@ reg_t reg_from_bytes(size_t len, const uint8_t* bytes)
 
 bool mmu_t::mmio_ok(reg_t addr, access_type type)
 {
-  // Disallow access to debug region when not in debug mode
-  if (addr >= DEBUG_START && addr <= DEBUG_END && proc && !proc->state.debug_mode)
-    return false;
-
   return true;
 }