i2c: rcar: use proper type for timeout

wait_event_timeout returns long, not int.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
(cherry picked from commit b6763d0d

)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>