Drop extraneous duplicate header includes

Signed-off-by: Bryce Harrington <b.harrington@samsung.com>

clients/flower.c

@@ -26,7 +26,6 @@
 #include <string.h>
 #include <time.h>
 #include <math.h>
-#include <time.h>
 #include <cairo.h>
 #include <sys/time.h>
 

clients/smoke.c

@@ -26,7 +26,6 @@
 #include <string.h>
 #include <time.h>
 #include <math.h>
-#include <time.h>
 #include <cairo.h>
 
 #include <wayland-client.h>

src/compositor-drm.c

@@ -25,7 +25,6 @@
 
 #include <errno.h>
 #include <stdlib.h>
-#include <stdlib.h>
 #include <ctype.h>
 #include <string.h>
 #include <fcntl.h>

src/compositor-fbdev.c

@@ -39,8 +39,6 @@
 
 #include <libudev.h>
 
-#include "config.h"
-
 #include "compositor.h"
 #include "launcher-util.h"
 #include "pixman-renderer.h"