added poll api passthrough

src/main.cpp

@@ -0,0 +1,21 @@
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/uart.h>
+
+const struct device *test_uart = DEVICE_DT_GET(DT_ALIAS(testuart));
+
+
+
+int main(void) {
+    
+    const char msg [] = "Hello World";
+
+    while (1) {
+        for (char c : msg) {
+            uart_poll_out(test_uart, c);
+        }
+
+        k_sleep(K_MSEC(100));
+    }
+    return 0;
+}