arm: implement invalidate_icache_all on ARM11

In EFI sub-system we rely on invalidate_icache_all() to invalidate the
instruction cache after loading binaries. Add the missing implementation on
ARM1136, ARM1176.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

arch/arm/cpu/arm11/cpu.c

@@ -117,3 +117,15 @@ void enable_caches(void)
 #endif
 }
 #endif
+
+#if !CONFIG_IS_ENABLED(SYS_ICACHE_OFF)
+/* Invalidate entire I-cache */
+void invalidate_icache_all(void)
+{
+	unsigned long i = 0;
+
+	asm ("mcr p15, 0, %0, c7, c5, 0" : : "r" (i));
+}
+#else
+void invalidate_icache_all(void) {}
+#endif