ARM: mxs: look up timrot clock from device tree

Change call clk_get_sys() to of_clk_get() to look up timrot clock from
device tree, so that the clk_register_clkdev() call for timrot can be
saved in clock driver.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

drivers/clk/mxs/clk-imx23.c

@@ -159,8 +159,6 @@ int __init mx23_clocks_init(void)
 		of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
 	}
 
-	clk_register_clkdev(clks[clk32k], NULL, "timrot");
-
 	for (i = 0; i < ARRAY_SIZE(clks_init_on); i++)
 		clk_prepare_enable(clks[clks_init_on[i]]);
 

drivers/clk/mxs/clk-imx28.c

@@ -237,7 +237,6 @@ int __init mx28_clocks_init(void)
 		of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
 	}
 
-	clk_register_clkdev(clks[xbus], NULL, "timrot");
 	clk_register_clkdev(clks[enet_out], NULL, "enet_out");
 
 	for (i = 0; i < ARRAY_SIZE(clks_init_on); i++)