ARM: davinci: convert platform code to use clk_prepare/clk_unprepare

As a first step towards migrating davinci platforms to use common clock
framework, replace all instances of clk_enable() with clk_prepare_enable()
and clk_disable() with clk_disable_unprepare(). Until the platform is
switched to use the CONFIG_HAVE_CLK_PREPARE Kconfig variable, this just
adds a might_sleep() call and would work without any issues.

This will make it easy later to switch to common clk based implementation
of clk driver from DaVinci specific driver.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Reviewed-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
diff --git a/arch/arm/mach-davinci/board-neuros-osd2.c b/arch/arm/mach-davinci/board-neuros-osd2.c
index 144bf31..3e3e3af 100644
--- a/arch/arm/mach-davinci/board-neuros-osd2.c
+++ b/arch/arm/mach-davinci/board-neuros-osd2.c
@@ -188,7 +188,7 @@
 	struct davinci_soc_info *soc_info = &davinci_soc_info;
 
 	aemif_clk = clk_get(NULL, "aemif");
-	clk_enable(aemif_clk);
+	clk_prepare_enable(aemif_clk);
 
 	if (HAS_ATA) {
 		if (HAS_NAND)