mmc: dw_mmc-pltfm: Remove unused <linux/clk.h>

As of commit 4cdc2ec1 ("mmc: dw_mmc: move rockchip related code
to a separate file"), dw_mmc-pltfm.c no longer uses the clock API.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Link: https://lore.kernel.org/r/20210527194226.1705607-1-geert@linux-m68k.orgSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/dw_mmc-pltfm.c

@@ -17,7 +17,6 @@
 #include <linux/mmc/host.h>
 #include <linux/mmc/mmc.h>
 #include <linux/of.h>
-#include <linux/clk.h>
 
 #include "dw_mmc.h"
 #include "dw_mmc-pltfm.h"