rockchip: remove log2 reimplementation from clock drivers

The already available ilog2 function does exactly the same in the common
case than the log2 function the current clock-driver reimplement.
So, simply move to that one.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/clk/rockchip/clk_rk3288.c b/drivers/clk/rockchip/clk_rk3288.c
index e00feb0..c07203d 100644
--- a/drivers/clk/rockchip/clk_rk3288.c
+++ b/drivers/clk/rockchip/clk_rk3288.c
@@ -20,6 +20,7 @@
 #include <dm/device-internal.h>
 #include <dm/lists.h>
 #include <dm/uclass-internal.h>
+#include <linux/log2.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -186,11 +187,6 @@
 	return 0;
 }
 
-static inline unsigned int log2(unsigned int value)
-{
-	return fls(value) - 1;
-}
-
 static int rkclk_configure_ddr(struct rk3288_cru *cru, struct rk3288_grf *grf,
 			       unsigned int hz)
 {
@@ -421,11 +417,11 @@
 	aclk_div = GPLL_HZ / PERI_ACLK_HZ - 1;
 	assert((aclk_div + 1) * PERI_ACLK_HZ == GPLL_HZ && aclk_div < 0x1f);
 
-	hclk_div = log2(PERI_ACLK_HZ / PERI_HCLK_HZ);
+	hclk_div = ilog2(PERI_ACLK_HZ / PERI_HCLK_HZ);
 	assert((1 << hclk_div) * PERI_HCLK_HZ ==
 		PERI_ACLK_HZ && (hclk_div < 0x4));
 
-	pclk_div = log2(PERI_ACLK_HZ / PERI_PCLK_HZ);
+	pclk_div = ilog2(PERI_ACLK_HZ / PERI_PCLK_HZ);
 	assert((1 << pclk_div) * PERI_PCLK_HZ ==
 		PERI_ACLK_HZ && (pclk_div < 0x4));