csky: Remove duplicate include in arch/csky/kernel/entry.S

'asm/setup.h' included in 'arch/csky/kernel/entry.S' is duplicated.
Signed-off-by: Zhang Yunkai <zhang.yunkai@zte.com.cn>
Signed-off-by: Guo Ren <guoren@kernel.org>

arch/csky/kernel/entry.S

@@ -9,7 +9,6 @@
 #include <asm/unistd.h>
 #include <asm/asm-offsets.h>
 #include <linux/threads.h>
-#include <asm/setup.h>
 #include <asm/page.h>
 #include <asm/thread_info.h>