udev_input.c: Look for "ID_INPUT_KEY", not "ID_INPUT_KEYBOARD"

This fixes programs using /dev/uinput to create a virtual keyboard failing
to be detected on startup. Usual symptom is some sort of GPIO-based
controller that looks like a keyboard to the OS and can control
EmulationStation, but fails to work in-game unless you restart the program
while the game is running (in which case udev_input.c's hotplug code, which
was using the correct key, would pick it up).

input/drivers/udev_input.c

@@ -96,7 +96,7 @@ enum udev_input_dev_type
 /* NOTE: must be in sync with enum udev_input_dev_type */
 static const char *g_dev_type_str[] =
 {
-   "ID_INPUT_KEYBOARD",
+   "ID_INPUT_KEY",
    "ID_INPUT_MOUSE",
    "ID_INPUT_TOUCHPAD"
 };