fix(m68k): correct SR register read (#2161)

The SR register in the `CPUM68KState` struct does not contain the value
of the lower 5 flags. To compute them, we must OR the CCR values with
the SR register to get the true SR value.

qemu/target/m68k/helper.c

@@ -591,6 +591,10 @@ uint32_t HELPER(sats)(uint32_t val, uint32_t v)
     return val;
 }
 
+uint32_t cpu_m68k_get_sr(CPUM68KState *env) {
+    return env->sr | cpu_m68k_get_ccr(env);
+}
+
 void cpu_m68k_set_sr(CPUM68KState *env, uint32_t sr)
 {
     env->sr = sr & 0xffe0;