simplefb: Include clk.h

This driver uses the consumer API, so include clk.h explicitly
instead of impliclty through the provider API.

Cc: Luc Verhaegen <[e-mail]>
Cc: Hans de Goede <[e-mail]>
Acked-by: Geert Uytterhoeven <[e-mail]>
Cc: Maxime Ripard <[e-mail]>
Cc: David Herrmann <[e-mail]>
Cc: Tomi Valkeinen <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/video/fbdev/simplefb.c

···
 #include <linux/module.h>
 #include <linux/platform_data/simplefb.h>
 #include <linux/platform_device.h>
+#include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/of_platform.h>