ARM: ux500: Staticise ux500_soc_attr

This variable is not used outside of the file that it's declared in, so
reduce the scope to the local file.
Signed-off-by: NThierry Reding <treding@nvidia.com>
[Also add const marker after suggestion from Lee Jones]
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

arch/arm/mach-ux500/cpu.c

@@ -125,7 +125,7 @@ static void __init soc_info_populate(struct soc_device_attribute *soc_dev_attr,
 	soc_dev_attr->revision = ux500_get_revision();
 }
 
-struct device_attribute ux500_soc_attr =
+static const struct device_attribute ux500_soc_attr =
 	__ATTR(process,  S_IRUGO, ux500_get_process,  NULL);
 
 struct device * __init ux500_soc_device_init(const char *soc_id)