dma-mapping: remove the dma_direct_set_offset export

Drop the dma_direct_set_offset export and move the declaration to
dma-map-ops.h now that the Allwinner drivers have stopped calling it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
diff --git a/arch/arm/mach-omap1/usb.c b/arch/arm/mach-omap1/usb.c
index ba85662..86d3b3c 100644
--- a/arch/arm/mach-omap1/usb.c
+++ b/arch/arm/mach-omap1/usb.c
@@ -9,7 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
-#include <linux/dma-mapping.h>
+#include <linux/dma-map-ops.h>
 #include <linux/io.h>
 
 #include <asm/irq.h>