xtensa: nommu: move init_mmu stub to nommu_context.h

mmu_context.h is not used in nommu configuration, nommu_context.h is
used instead.
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/asm/mmu_context.h

@@ -50,11 +50,7 @@ DECLARE_PER_CPU(unsigned long, asid_cache);
 #define ASID_MASK	((1 << XCHAL_MMU_ASID_BITS) - 1)
 #define ASID_INSERT(x)	(0x03020001 | (((x) & ASID_MASK) << 8))
 
-#ifdef CONFIG_MMU
 void init_mmu(void);
-#else
-static inline void init_mmu(void) { }
-#endif
 
 static inline void set_rasid_register (unsigned long val)
 {

arch/xtensa/include/asm/nommu_context.h

+static inline void init_mmu(void)
+{
+}
+
 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 {
 }