Use DevMgr::getNextDevicePath()

Also, a fix for number of args passed for accelsim.

Updated to newest version of DriverFramework.

DF drvices show up now in list_devices

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/platforms/posix/drivers/accelsim/accelsim.cpp

@@ -1182,6 +1182,10 @@ accelsim_main(int argc, char *argv[])
 		}
 	}
 
+	if (argc <= 1) {
+		accelsim::usage();
+		return 1;
+	}
 	const char *verb = argv[myoptind];
 
 	/*