Samsung YP-R0/YP-R1 refactoring

This patch includes some refactoring:
- renaming according to Rockbox guidelines
- GPIO code merging, still with target defines
- some simplification in firmware/SOURCES

Change-Id: I7fd95aece53f40efdf8caac22348376615795431

firmware/target/hosted/samsungypr/gpio-ypr.c

@@ -0,0 +1,48 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ *
+ * Module wrapper for GPIO, using kernel module of Samsung YP-R0/YP-R1
+ *
+ * Copyright (c) 2011 Lorenzo Miori
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <gpio-ypr.h> /* includes common ioctl device definitions */
+#include <sys/ioctl.h>
+
+static int gpio_dev = 0;
+
+void gpio_init(void)
+{
+    gpio_dev = open(GPIO_DEVICE, O_RDONLY);
+    if (gpio_dev < 0)
+        printf("GPIO device open error!");
+}
+
+void gpio_close(void)
+{
+    if (gpio_dev >= 0)
+        close(gpio_dev);
+}
+
+int gpio_control(int request, int num, int mode, int val)
+{
+    struct gpio_info r = { .num = num, .mode = mode, .val = val, };
+    return ioctl(gpio_dev, request, &r);
+}