!4950  arm64: head.S: always initialize PSTATE

Merge Pull Request from: @ci-robot 
 
PR sync from: Li Zetao <lizetao1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/MXC66ZXKFV2FNFEACXCTN3PD7V742GXJ/ 
 
https://gitee.com/openeuler/kernel/issues/I95U8R 
 
Link:https://gitee.com/openeuler/kernel/pulls/4950 

Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com> 
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>