nios2: don't leave NULLs in sys_call_table[]

stable inclusion
from stable-v5.10.138
commit 1d2c89dc4837cdd9d0e672ec6d3357cd1362b1b7
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=1d2c89dc4837cdd9d0e672ec6d3357cd1362b1b7



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commit 45ec746c upstream.

fill the gaps in there with sys_ni_syscall, as everyone does...

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>