mmc-host: vub300: use setup_timer() helper.

Use setup_timer function instead of initializing timer with the
   function and data fields.

Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>