syscall symbols now work as global symbols

riscemu/Syscall.py

@@ -167,6 +167,6 @@ class SyscallInterface:
         scall.cpu.exit_code = scall.registers.get('a0')
 
     def get_syscall_symbols(self):
-        symbols = dict()
-        for num, name in SYSCALLS.items():
-            symbols['SCALL_' + name.upper()] = num
+        return {
+            ('SCALL_' + name.upper()): num for num, name in SYSCALLS.items()
+        }