Fix USB initilaize on LUFA

- Add print messages of USB intialize procesure.
- call out sei() in earlier stage. LUFA API doc of USB_Init() says:
interrupts must be enabled within 500ms ... to ensure that the host does
not time out whilst enumerating the device
- remove matrix_init() from suspend_wakeup_init(). It is not needed in
  fact and if matrix_init() takes long time to initialize it prevents
host emnumerating the device.

common/keyboard.c

@@ -54,9 +54,6 @@ static bool has_ghost_in_row(uint8_t row)
 
 void keyboard_init(void)
 {
-    // TODO: configuration of sendchar impl
-    print_set_sendchar(sendchar);
-
     timer_init();
     matrix_init();
 #ifdef PS2_MOUSE_ENABLE

common/suspend.c

@@ -51,8 +51,7 @@ bool suspend_wakeup_condition(void)
 // run immediately after wakeup
 void suspend_wakeup_init(void)
 {
-    // clear matrix and keyboard state
-    matrix_init();
+    // clear keyboard state
     clear_keyboard();
 #ifdef BACKLIGHT_ENABLE
     backlight_init();

protocol/lufa/lufa.c

@@ -531,19 +531,24 @@ static void SetupHardware(void)
 
     // for Console_Task
     USB_Device_EnableSOFEvents();
+    print_set_sendchar(sendchar);
 }
 
 int main(void)  __attribute__ ((weak));
 int main(void)
 {
     SetupHardware();
+    sei();
+    while (USB_DeviceState != DEVICE_STATE_Configured) ;
+    print("USB configured.\n");
+
     keyboard_init();
     host_set_driver(&lufa_driver);
 #ifdef SLEEP_LED_ENABLE
     sleep_led_init();
 #endif
-    sei();
 
+    print("Keyboard start.\n");
     while (1) {
         while (USB_DeviceState == DEVICE_STATE_Suspended) {
             suspend_power_down();