Replace sleep with px4_sleep

This is another step to isolate time from the system.

src/systemcmds/pwm/pwm.cpp

@@ -752,7 +752,7 @@ err_out_no_test:
 		fds.events = POLLIN;
 
 		PX4_WARN("Running 5 steps. WARNING! Motors will be live in 5 seconds\nPress any key to abort now.");
-		sleep(5);
+		px4_sleep(5);
 
 		if (::ioctl(fd, PWM_SERVO_SET_MODE, PWM_SERVO_ENTER_TEST_MODE) < 0) {
 				PX4_ERR("Failed to Enter pwm test mode");

src/systemcmds/tests/hrt_test/hrt_test.cpp

@@ -76,7 +76,7 @@ int HRTTest::main()
 	PX4_INFO("Start time %llu\n", (unsigned long long)t);
 
 	t = hrt_absolute_time();
-	sleep(1);
+	px4_sleep(1);
 	elt = hrt_elapsed_time(&t);
 	PX4_INFO("Elapsed time %llu in 1 sec (sleep)\n", (unsigned long long)elt);
 	PX4_INFO("Start time %llu\n", (unsigned long long)t);
@@ -86,7 +86,7 @@ int HRTTest::main()
 	PX4_INFO("HRT_CALL %d\n", hrt_called(&t1));
 
 	hrt_call_after(&t1, update_interval, timer_expired, (void *)nullptr);
-	sleep(2);
+	px4_sleep(2);
 	PX4_INFO("HRT_CALL - %d\n", hrt_called(&t1));
 	hrt_cancel(&t1);
 	PX4_INFO("HRT_CALL + %d\n", hrt_called(&t1));

src/systemcmds/tests/test_uart_console.c

@@ -94,7 +94,7 @@ int test_uart_console(int argc, char *argv[])
 		write(uart_usb, sample_uart_usb, sizeof(sample_uart_usb));
 		printf(".");
 		fflush(stdout);
-		sleep(1);
+		px4_sleep(1);
 	}
 
 //	uint64_t start_time = hrt_absolute_time();

src/systemcmds/top/top.c

@@ -80,7 +80,7 @@ top_main(int argc, char *argv[])
 	if (argc > 1) {
 		if (!strcmp(argv[1], "once")) {
 			print_load(curr_time, 1, &load);
-			sleep(1);
+			px4_sleep(1);
 			print_load(hrt_absolute_time(), 1, &load);
 
 		} else {