LoongArch: fix __ffs not defined compile error

LoongArch inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I79UUL



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LoongArch code can not compile,the reason is __ffs is not found,
chage the bitops.h include order to make it fine.

Fixes: 0cba0556 ("cpumask: introduce for_each_cpu_or")

Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>