nios2: page fault et.al. are *not* restartable syscalls...

stable inclusion
from stable-v5.10.138
commit d29cdf865ae133810e55d15867d9ebf45fc75f37
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60QFD

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d29cdf865ae133810e55d15867d9ebf45fc75f37



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

commit 8535c239 upstream.

make sure that ->orig_r2 is negative for everything except
the syscalls.

Fixes: 82ed08dd ("nios2: Exception handling")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>