wiringPi: Refactor source codes including fixes for collisions that'd…

… occur

Replace WiringPi header files to the ODROID specific files
 - Note: To avoid unforeseen errors when working with Python Wrapper.
   Python Wrapper doesn't recognize the ODROID specific header files and
   its introduced functions, declarations. So just thought that fixing
   Python Wrapper is much more complicated than replacing the header files
   and it seems more suitable for the later updates.
Fix messaging implicit declaration of core functions
Fix collisions of functions/declarations by header files
 - Note: In each ODROID sources, the prefix '_' have to be added to the
   core functions in order to avoid the collisions that non-static function
   follows static function. This is because of importing "wiringPi.h" header
   file that has extern core functions which names the same as listed in
   each ODROID source code file. So the core functions that exported from
   here must have that prefix, and only to be assigned its pointer to the
   "libodroid" structure.

Change-Id: Ia927c7946cfb6ca6ce3a02530936325e1acb0620

gpio/Makefile

@@ -30,9 +30,6 @@ ifneq ($V,1)
 Q ?= @
 endif
 
-# BRAND_NAME = Pi
-BRAND_NAME = Odroid
-
 #DEBUG	= -g -O0
 DEBUG	= -O2
 CC	= gcc
@@ -44,16 +41,8 @@ LIBS    = -lwiringPi -lwiringPiDev -lpthread -lrt -lm -lcrypt
 
 # May not need to  alter anything below this line
 ###############################################################################
-ifeq ($(BRAND_NAME), Odroid)
-
-SRC	=	gpio_odroid.c readall_odroid.c pins.c
-
-else
-
 SRC	=	gpio.c readall.c pins.c
 
-endif
-
 OBJ	=	$(SRC:.c=.o)
 
 all:		gpio