mmc: dw_mmc-pltfm: move probe and remove below dt match table

In a subsquent patch probe will need to do some handling of data from
the dt match table. So to prevent the need for forward declarations,
move probe and remove below the match table.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>