modetest: remove buffer.h from SRC in Makefile

otherwise make clean would delete this source file.

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

modetest/Makefile

@@ -7,7 +7,7 @@ LFLAGS = -L/usr/local/lib -L/usr/lib/arm-linux-gnueabihf
 
 LIBS = -ldrm 
 
-SRC=msmdumb.c libmsm.c buffers.c msmmodetest.c buffers.h
+SRC=msmdumb.c libmsm.c buffers.c msmmodetest.c
 OBJ=$(patsubst %.c,%.o,$(SRC))
 CC = $(CROSS_COMPILE)gcc