OMAP3 clock: Check return values for clk_get()

This patch checks if clk_get() returned success for
the clocks used in function omap2_clk_arch_init().

This version incorporates review comments from
Kevin Hilman and Paul Walmsley.
Signed-off-by: Sanjeev Premi <premi@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/mach-omap2/clock34xx.c

@@ -21,6 +21,7 @@
 #include <linux/delay.h>
 #include <linux/clk.h>
 #include <linux/io.h>
+#include <linux/err.h>
 
 #include <plat/cpu.h>
 #include <plat/clock.h>
@@ -286,6 +287,7 @@ static int __init omap3xxx_clk_arch_init(void)
 {
 	struct clk *osc_sys_ck, *dpll1_ck, *arm_fck, *core_ck;
 	unsigned long osc_sys_rate;
+	bool err = 0;
 
 	if (!cpu_is_omap34xx())
 		return 0;
@@ -295,9 +297,23 @@ static int __init omap3xxx_clk_arch_init(void)
 
 	/* XXX test these for success */
 	dpll1_ck = clk_get(NULL, "dpll1_ck");
+	if (WARN(IS_ERR(dpll1_ck), "Failed to get dpll1_ck.\n"))
+		err = 1;
+
 	arm_fck = clk_get(NULL, "arm_fck");
+	if (WARN(IS_ERR(arm_fck), "Failed to get arm_fck.\n"))
+		err = 1;
+
 	core_ck = clk_get(NULL, "core_ck");
+	if (WARN(IS_ERR(core_ck), "Failed to get core_ck.\n"))
+		err = 1;
+
 	osc_sys_ck = clk_get(NULL, "osc_sys_ck");
+	if (WARN(IS_ERR(osc_sys_ck), "Failed to get osc_sys_ck.\n"))
+		err = 1;
+
+	if (err)
+		return -ENOENT;
 
 	/* REVISIT: not yet ready for 343x */
 	if (clk_set_rate(dpll1_ck, mpurate))