clk: wrap I/O access for improved portability

the common clock drivers were motivated/initiated by ARM development
and apparently assume little endian peripherals

wrap register/peripherals access in the common code (div, gate, mux)
in preparation of adding COMMON_CLK support for other platforms

Signed-off-by: Gerhard Sittig <gsi@denx.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 749372f..8d3009e 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -104,7 +104,7 @@
 	struct clk_divider *divider = to_clk_divider(hw);
 	unsigned int div, val;
 
-	val = readl(divider->reg) >> divider->shift;
+	val = clk_readl(divider->reg) >> divider->shift;
 	val &= div_mask(divider);
 
 	div = _get_div(divider, val);
@@ -230,11 +230,11 @@
 	if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
 		val = div_mask(divider) << (divider->shift + 16);
 	} else {
-		val = readl(divider->reg);
+		val = clk_readl(divider->reg);
 		val &= ~(div_mask(divider) << divider->shift);
 	}
 	val |= value << divider->shift;
-	writel(val, divider->reg);
+	clk_writel(val, divider->reg);
 
 	if (divider->lock)
 		spin_unlock_irqrestore(divider->lock, flags);