mmc: dw_mmc-pltfm: include 'dw_mmc-pltfm.h'

Include 'dw_mmc-pltfm.h' header file in order to fix the following
sparse warnings:

drivers/mmc/host/dw_mmc-pltfm.c:36:5: warning: symbol 'dw_mci_pltfm_register' was not declared. Should it be static?
drivers/mmc/host/dw_mmc-pltfm.c:94:1: warning: symbol 'dw_mci_pltfm_pmops' was not declared. Should it be static?
drivers/mmc/host/dw_mmc-pltfm.c:118:5: warning: symbol 'dw_mci_pltfm_remove' was not declared. Should it be static?

Suggested-by: Dan Carpenter <[e-mail]>
Signed-off-by: Jingoo Han <[e-mail]>
Acked-by: Seungwon Jeon <[e-mail]>
Signed-off-by: Chris Ball <[e-mail]>

drivers/mmc/host/dw_mmc-pltfm.c

···
 #include <linux/of.h>
 
 #include "dw_mmc.h"
+#include "dw_mmc-pltfm.h"
 
 static void dw_mci_rockchip_prepare_command(struct dw_mci *host, u32 *cmdr)
 {