mmc: dw_mmc: exynos: Remove unnecessary use of of_match_ptr()

'dw_mci_exynos_match' is always compiled in. Hence of_match_ptr
is not required.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>