csky: use asm-generic/mmu_context.h for no-op implementations

Signed-off-by: Nicholas Piggin <[e-mail]>
Acked-by: Guo Ren <[e-mail]>
Cc: [e-mail]
Signed-off-by: Arnd Bergmann <[e-mail]>

arch/csky/include/asm/mmu_context.h

···
 #define cpu_asid(mm)		(atomic64_read(&mm->context.asid) & ASID_MASK)
 
 #define init_new_context(tsk,mm)	({ atomic64_set(&(mm)->context.asid, 0); 0; })
-#define activate_mm(prev,next)		switch_mm(prev, next, current)
-
-#define destroy_context(mm)		do {} while (0)
-#define enter_lazy_tlb(mm, tsk)		do {} while (0)
-#define deactivate_mm(tsk, mm)		do {} while (0)
 
 void check_and_switch_context(struct mm_struct *mm, unsigned int cpu);
 
···
 
 	flush_icache_deferred(next);
 }
+
+#include <asm-generic/mmu_context.h>
+
 #endif /* __ASM_CSKY_MMU_CONTEXT_H */