Add and fix copyright notices for better GPL compliance (thanks @naehrwert and @CTCaer).

exosphere/src/uart.c

@@ -1,9 +1,24 @@
+/*
+ * Copyright (c) 2018 naehrwert
+ * Copyright (c) 2018 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+ 
 #include "timers.h"
 #include "uart.h"
 #include "misc.h"
 
-/* Adapted from https://github.com/nwert/hekate/blob/master/hwinit/uart.c */
-
 void uart_select(UartDevice dev) {
     unsigned int id = (unsigned int)dev;
     PINMUX_AUX_UARTn_TX_0(id) = 0; /* UART */