Fix warning print format strings being truncated #308

Debian 10 (Buster) has gcc 8.2 which warns about:

error: ‘%s’ directive output may be truncated writing up to 19 bytes into a region of size between 10 and 59 [-Werror=format-truncation=]
  snprintf(path, sizeof(path), "%s/%s/state", ocp_dir, pinmux_dir);

source/c_pinmux.c

@@ -9,7 +9,7 @@
 BBIO_err set_pin_mode(const char *key, const char *mode)
 {
 	// char ocp_dir[] defined in common.h
-	char path[60]; // "/sys/devices/platform/ocp/ocp:P#_##_pinmux/state"
+	char path[100]; // "/sys/devices/platform/ocp/ocp:P#_##_pinmux/state"
 	char pinmux_dir[20]; // "ocp:P#_##_pinmux"
 	char pin[6]; //"P#_##"
 	FILE *f = NULL;

source/common.c

@@ -636,12 +636,10 @@ BBIO_err load_device_tree(const char *name)
 {
     char line[256];
     FILE *file = NULL;
-
+    char slots[100];
 #ifdef BBBVERSION41
-    char slots[41];
     snprintf(ctrl_dir, sizeof(ctrl_dir), "/sys/devices/platform/bone_capemgr");
 #else
-    char slots[40];
     build_path("/sys/devices", "bone_capemgr", ctrl_dir, sizeof(ctrl_dir));
 #endif
 
@@ -698,11 +696,10 @@ BBIO_err load_device_tree(const char *name)
 int device_tree_loaded(const char *name)
 {
     FILE *file = NULL;
+    char slots[100];
 #ifdef BBBVERSION41
-    char slots[41];
     snprintf(ctrl_dir, sizeof(ctrl_dir), "/sys/devices/platform/bone_capemgr");
 #else
-    char slots[40];
     build_path("/sys/devices", "bone_capemgr", ctrl_dir, sizeof(ctrl_dir));
 #endif
     char line[256];
@@ -755,11 +752,10 @@ int device_tree_loaded(const char *name)
 BBIO_err unload_device_tree(const char *name)
 {
     FILE *file = NULL;
+    char slots[100];
 #ifdef BBBVERSION41
-    char slots[41];
     snprintf(ctrl_dir, sizeof(ctrl_dir), "/sys/devices/platform/bone_capemgr");
 #else
-    char slots[40];
     build_path("/sys/devices", "bone_capemgr", ctrl_dir, sizeof(ctrl_dir));
 #endif
     char line[256];