ARM: OMAP: fix return value check in beagle_opp_init()

In case of error, the function omap_device_get_by_hwmod_name()
returns ERR_PTR() not NULL pointer. The NULL test in the return
value check should be replaced with IS_ERR().

dpatch engine is used to auto generated this patch.
(https://github.com/weiyj/dpatch)
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NKevin Hilman <khilman@ti.com>

arch/arm/mach-omap2/board-omap3beagle.c

@@ -466,7 +466,7 @@ static void __init beagle_opp_init(void)
 		mpu_dev = omap_device_get_by_hwmod_name("mpu");
 		iva_dev = omap_device_get_by_hwmod_name("iva");
 
-		if (!mpu_dev || !iva_dev) {
+		if (IS_ERR(mpu_dev) || IS_ERR(iva_dev)) {
 			pr_err("%s: Aiee.. no mpu/dsp devices? %p %p\n",
 				__func__, mpu_dev, iva_dev);
 			return;