MIPS: loongson: common: rtc: make loongson_rtc_resources static

Make loongson_rtc_resources static to eliminate the following
sparse warning:
warning: symbol 'loongson_rtc_resources' was not declared. Should it be static?
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8529/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/loongson/common/rtc.c

@@ -14,7 +14,7 @@
 #include <linux/platform_device.h>
 #include <linux/mc146818rtc.h>
 
-struct resource loongson_rtc_resources[] = {
+static struct resource loongson_rtc_resources[] = {
 	{
 		.start	= RTC_PORT(0),
 		.end	= RTC_PORT(1),