MIPS: Loongson: Do not initialise statics to 0

Fix the following checkpatch error:

ERROR: do not initialise statics to 0
#125: FILE: loongson64/numa.c:125:
+	static unsigned long num_physpages = 0;

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>