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>