tests: logging: Improve compatibility with 64-bit platforms

Use %zu format specifier for size_t type to ensure compatibility with both
32-bit and 64-bit platforms.

Signed-off-by: Tim Pambor <[email protected]>

Author: tpambor

tests/subsys/logging/log_backend_uart/src/main.c

@@ -68,7 +68,7 @@ ZTEST_F(log_backend_uart, test_log_backend_uart_multi_instance)
 
 		tx_len = uart_emul_get_tx_data(fixture->dev[i], tx_content, sizeof(tx_content));
 		zassert_equal(tx_len, strlen(TEST_DATA),
-			      "%d: TX buffer length does not match. Expected %d, got %d",
+			      "%zu: TX buffer length does not match. Expected %zu, got %zu",
 			      i, strlen(TEST_DATA), tx_len);
 		zassert_mem_equal(tx_content, TEST_DATA, strlen(TEST_DATA));
 	}

tests/subsys/logging/log_core_additional/src/log_test.c

@@ -300,7 +300,7 @@ ZTEST(test_log_core_additional, test_log_early_logging)
 		}
 
 		zassert_equal(backend1_cb.total_logs, backend1_cb.counter,
-			      "Unexpected amount of messages received. %d",
+			      "Unexpected amount of messages received. %zu",
 			      backend1_cb.counter);
 	}
 }