xtensa: nommu: provide __invalidate_dcache_page_alias stub

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/asm/cacheflush.h

@@ -67,6 +67,8 @@ extern void __invalidate_dcache_page_alias(unsigned long, unsigned long);
 #else
 static inline void __flush_invalidate_dcache_page_alias(unsigned long virt,
 							unsigned long phys) { }
+static inline void __invalidate_dcache_page_alias(unsigned long virt,
+						  unsigned long phys) { }
 #endif
 #if defined(CONFIG_MMU) && (ICACHE_WAY_SIZE > PAGE_SIZE)
 extern void __invalidate_icache_page_alias(unsigned long, unsigned long);