drivers/rtc/rtc-coh901331.c: use clk_prepare_enable() and clk_disable_unprepare()

clk_prepare_enable and clk_disable_unprepare combine clk_prepare and
clk_enable, and clk_disable and clk_unprepare.  They make the code more
concise, and ensure that clk_unprepare is called when clk_enable fails.

A simplified version of the semantic patch that introduces calls to these
functions is as follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression e;
@@

- clk_prepare(e);
- clk_enable(e);
+ clk_prepare_enable(e);

@@
expression e;
@@

- clk_disable(e);
- clk_unprepare(e);
+ clk_disable_unprepare(e);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-coh901331.c

@@ -276,8 +276,7 @@ static void coh901331_shutdown(struct platform_device *pdev)
 
 	clk_enable(rtap->clk);
 	writel(0, rtap->virtbase + COH901331_IRQ_MASK);
-	clk_disable(rtap->clk);
-	clk_unprepare(rtap->clk);
+	clk_disable_unprepare(rtap->clk);
 }
 
 static struct platform_driver coh901331_driver = {