samples: modules: lvgl: fix integer overflow

`lv_task_handler()` returns a `uint32_t`, but `k_msleep` takes a
`int32_t`.

If no timer exists, `lv_task_handler()` returns `UINT32_MAX` to indicate
that we should wait forever. However, this gets auto-cast to `-1`,
indicating to `k_msleep` to not wait at all, creating a busy loop.

Hence, a clamping to `[0, INT32_MAX]` is required.

Signed-off-by: Martin Stumpf <[email protected]>

Author: Finomnis

samples/modules/lvgl/accelerometer_chart/src/main.c

@@ -89,7 +89,9 @@ int main(void)
 	display_blanking_off(display_dev);
 
 	while (1) {
-		k_msleep(lv_task_handler());
+		uint32_t sleep_ms = lv_task_handler();
+
+		k_msleep(MIN(sleep_ms, INT32_MAX));
 	}
 
 	return 0;

samples/modules/lvgl/demos/src/main.c

@@ -40,7 +40,9 @@ int main(void)
 	display_blanking_off(display_dev);
 
 	while (1) {
-		k_msleep(lv_task_handler());
+		uint32_t sleep_ms = lv_task_handler();
+
+		k_msleep(MIN(sleep_ms, INT32_MAX));
 	}
 
 	return 0;