clk: mxs: add clkdev lookup for pwm

Add pwm clock lookup for imx23 and imx28 booting from device tree.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/drivers/clk/mxs/clk-imx23.c b/drivers/clk/mxs/clk-imx23.c
index 40ad638..c14b021 100644
--- a/drivers/clk/mxs/clk-imx23.c
+++ b/drivers/clk/mxs/clk-imx23.c
@@ -189,6 +189,7 @@
 		}
 
 	clk_register_clkdev(clks[clk32k], NULL, "timrot");
+	clk_register_clkdev(clks[pwm], NULL, "80064000.pwm");
 	clk_register_clkdevs(clks[hbus], hbus_lookups, ARRAY_SIZE(hbus_lookups));
 	clk_register_clkdevs(clks[xbus], xbus_lookups, ARRAY_SIZE(xbus_lookups));
 	clk_register_clkdevs(clks[uart], uart_lookups, ARRAY_SIZE(uart_lookups));
diff --git a/drivers/clk/mxs/clk-imx28.c b/drivers/clk/mxs/clk-imx28.c
index 003b0f3..365053f 100644
--- a/drivers/clk/mxs/clk-imx28.c
+++ b/drivers/clk/mxs/clk-imx28.c
@@ -314,6 +314,7 @@
 
 	clk_register_clkdev(clks[clk32k], NULL, "timrot");
 	clk_register_clkdev(clks[enet_out], NULL, "enet_out");
+	clk_register_clkdev(clks[pwm], NULL, "80064000.pwm");
 	clk_register_clkdevs(clks[hbus], hbus_lookups, ARRAY_SIZE(hbus_lookups));
 	clk_register_clkdevs(clks[xbus], xbus_lookups, ARRAY_SIZE(xbus_lookups));
 	clk_register_clkdevs(clks[uart], uart_lookups, ARRAY_SIZE(uart_lookups));