drm/armada: Include <linux/of.h>

Include <linux/of.h> to get declarations of of_node_put() and
of_device_is_available(). No functional changes.

Signed-off-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Sui Jingfeng <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/armada/armada_drv.c

···
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/of_graph.h>
 #include <linux/platform_device.h>