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-gate.c b/drivers/clk/clk-gate.c
index 2b28a00..4a58c55 100644
--- a/drivers/clk/clk-gate.c
+++ b/drivers/clk/clk-gate.c
@@ -58,7 +58,7 @@
 		if (set)
 			reg |= BIT(gate->bit_idx);
 	} else {
-		reg = readl(gate->reg);
+		reg = clk_readl(gate->reg);
 
 		if (set)
 			reg |= BIT(gate->bit_idx);
@@ -66,7 +66,7 @@
 			reg &= ~BIT(gate->bit_idx);
 	}
 
-	writel(reg, gate->reg);
+	clk_writel(reg, gate->reg);
 
 	if (gate->lock)
 		spin_unlock_irqrestore(gate->lock, flags);
@@ -89,7 +89,7 @@
 	u32 reg;
 	struct clk_gate *gate = to_clk_gate(hw);
 
-	reg = readl(gate->reg);
+	reg = clk_readl(gate->reg);
 
 	/* if a set bit disables this clk, flip it before masking */
 	if (gate->flags & CLK_GATE_SET_TO_DISABLE)