octeontx2-af: Fix an off by one in rvu_dbg_qsize_write()

stable inclusion
from stable-5.10.20
commit dae49384d0d7695540e2d75168f323cef1384810
bugzilla: 50608

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

[ Upstream commit 3a2eb515 ]

This code does not allocate enough memory for the NUL terminator so it
ends up putting it one character beyond the end of the buffer.

Fixes: 8756828a ("octeontx2-af: Add NPA aura and pool contexts to debugfs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>