bugfix: HRTMon ROM check fix

Author: midwan

src/ar.cpp

@@ -1820,7 +1820,7 @@ int hrtmon_load (void)
 			cart_type = CART_AR1200;
 			armodel = 1200;
 			hrtmem_start = 0x800000;
-		} else if (!memcmp (header, "HRT!", 4)) {
+		} else if (!memcmp (header, "HRT!", 4) || !memcmp(header + 1, "HRT!", 4)) {
 			cart_type = CART_HRTMON;
 		} else {
 			zfile_fclose (f);