dmaengine: rcar-hpbdma: Include linux/err.h

linux/err.h isn't implicitly included by the current headers on all
platforms, resulting in compilation failures due to implicit
declarations of IS_ERR and PTR_ERR. Fix this by including linux/err.h.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/sh/rcar-hpbdma.c

@@ -18,6 +18,7 @@
 
 #include <linux/dmaengine.h>
 #include <linux/delay.h>
+#include <linux/err.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>