makefile: cosmetic clean up in the makefile

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>

Makefile

-all: Vidctest
-Vidctest: queue.o message_queue.o decoder_driver_test.o
-	arm-linux-gnueabihf-gcc -pthread queue.o message_queue.o decoder_driver_test.o -o Vidctest
+all: vidctest
+
+vidctest: queue.o message_queue.o decoder_driver_test.o
+	arm-linux-gnueabihf-gcc -pthread queue.o message_queue.o decoder_driver_test.o -o vidctest
+
 queue.o:
 	arm-linux-gnueabihf-gcc -c queue.c
+
 message_queue.o:
 	arm-linux-gnueabihf-gcc -c message_queue.c
+
 decoder_driver_test.o:
 	arm-linux-gnueabihf-gcc -c decoder_driver_test.c
 
 clean:
 	-rm -f *.o
-	-rm -f Vidctest
+	-rm -f vidctest