USB: ohci-at91: prepare clk before calling enable

Replace clk_enable/disable with clk_prepare_enable/disable_unprepare to
avoid common clk framework warnings.

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
index 2ee1496..9677f68 100644
--- a/drivers/usb/host/ohci-at91.c
+++ b/drivers/usb/host/ohci-at91.c
@@ -41,17 +41,17 @@
 
 static void at91_start_clock(void)
 {
-	clk_enable(hclk);
-	clk_enable(iclk);
-	clk_enable(fclk);
+	clk_prepare_enable(hclk);
+	clk_prepare_enable(iclk);
+	clk_prepare_enable(fclk);
 	clocked = 1;
 }
 
 static void at91_stop_clock(void)
 {
-	clk_disable(fclk);
-	clk_disable(iclk);
-	clk_disable(hclk);
+	clk_disable_unprepare(fclk);
+	clk_disable_unprepare(iclk);
+	clk_disable_unprepare(hclk);
 	clocked = 0;
 }