ARM: Fix errata 411920 workarounds

Errata 411920 indicates that any "invalidate entire instruction cache"
operation can fail if the right conditions are present.  This is not
limited just to those operations in flush.c, but elsewhere.  Place the
workaround in the already existing __flush_icache_all() function
instead.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/include/asm/cacheflush.h

@@ -414,9 +414,14 @@ extern void __flush_dcache_page(struct address_space *mapping, struct page *page
 
 static inline void __flush_icache_all(void)
 {
+#ifdef CONFIG_ARM_ERRATA_411920
+	extern void v6_icache_inval_all(void);
+	v6_icache_inval_all();
+#else
 	asm("mcr	p15, 0, %0, c7, c5, 0	@ invalidate I-cache\n"
 	    :
 	    : "r" (0));
+#endif
 }
 
 #define ARCH_HAS_FLUSH_ANON_PAGE