sw64: fix bpf_user_pt_regs_t

Sunway inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I73KKS



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We have defined struct user_pt_regs and removed struct pt_regs from
UAPI. Fix the define of bpf_user_pt_regs_t accordingly.

Signed-off-by: Mao Minkai <maominkai@wxiat.com>
Reviewed-by: He Sheng <hesheng@wxiat.com>
Signed-off-by: Gu Zitao <guzitao@wxiat.com>