drivers/i2c/busses: use correct type for dma_map/unmap

commit 28772ac8711e4d7268c06e765887dd8cb6924f98 upstream.

dma_{un}map_* uses 'enum dma_data_direction' not 'enum dma_transfer_direction'.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>