csky: Support icache flush without specific instructions

Some CPUs don't support icache specific instructions to flush icache
lines in broadcast way. We use cpu control registers to flush local
icache and use IPI to notify other cores.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>

arch/csky/include/asm/cache.h

@@ -16,6 +16,7 @@ void dcache_wb_line(unsigned long start);
 
 void icache_inv_range(unsigned long start, unsigned long end);
 void icache_inv_all(void);
+void local_icache_inv_all(void *priv);
 
 void dcache_wb_range(unsigned long start, unsigned long end);
 void dcache_wbinv_all(void);