target/armv8: Handle instruction cache invalidate

Some armv8 target have separate i-cache and d-cache.
The actual code only handles the flush of the d-cache.

Change-Id: I61a223b43c71646bbbed8fa63825360c67700988
Signed-off-by: Adrien Grassein <agrassein@nanoxplore.com>
Signed-off-by: Adrien Charruel <acharruel@nanoxplore.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8655
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins

src/target/armv8.h

@@ -162,6 +162,7 @@ struct armv8_cache_common {
 	/* l2 external unified cache if some */
 	void *l2_cache;
 	int (*flush_all_data_cache)(struct target *target);
+	int (*invalidate_all_instruction_cache)(struct target *target);
 	int (*display_cache_info)(struct command_invocation *cmd,
 			struct armv8_cache_common *armv8_cache);
 };