extmod/nimble/hal/hal_uart: Fix HCI_TRACE format specifiers.

Makes this work consistently on unix and stm32 ports.

extmod/nimble/hal/hal_uart.c

@@ -66,7 +66,7 @@ void hal_uart_start_tx(uint32_t port) {
     }
 
     #if HCI_TRACE
-    printf("< [% 8d] %02x", mp_hal_ticks_ms(), mp_bluetooth_hci_cmd_buf[0]);
+    printf("< [% 8d] %02x", (int)mp_hal_ticks_ms(), mp_bluetooth_hci_cmd_buf[0]);
     for (size_t i = 1; i < len; ++i) {
         printf(":%02x", mp_bluetooth_hci_cmd_buf[i]);
     }
@@ -86,7 +86,7 @@ void mp_bluetooth_nimble_hci_uart_process(bool run_events) {
     int chr;
     while ((chr = mp_bluetooth_hci_uart_readchar()) >= 0) {
         #if HCI_TRACE
-        printf("> %02x (%d)\n", chr);
+        printf("> %02x\n", chr);
         #endif
         hal_uart_rx_cb(hal_uart_rx_arg, chr);