mmc: sh_mmcif: simplify clock divisor calculation

Replace ilog2(__rounddown_pow_of_two(x)) with the equivalent but much
simpler fls(x) - 1.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/sh_mmcif.c

@@ -16,6 +16,7 @@
  *
  */
 
+#include <linux/bitops.h>
 #include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
@@ -399,7 +400,7 @@ static void sh_mmcif_clock_control(struct sh_mmcif_host *host, unsigned int clk)
 		sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_SUP_PCLK);
 	else
 		sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_CLEAR &
-			(ilog2(__rounddown_pow_of_two(host->clk / clk)) << 16));
+				((fls(host->clk / clk) - 1) << 16));
 
 	sh_mmcif_bitset(host, MMCIF_CE_CLK_CTRL, CLK_ENABLE);
 }