powerpc: add CPU field to struct thread_info

mainline inclusion
from mainline-v5.16-rc1
commit 227d735d
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4Q94A


CVE: NA

------------------------------

The CPU field will be moved back into thread_info even when
THREAD_INFO_IN_TASK is enabled, so add it back to powerpc's definition
of struct thread_info.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Guan Jing <guanjing6@huawei.com>
Reviewed-by: Chen Hui <judy.chenhui@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>