net/mlx5: Fix uninitialized variable bug in outlen_write()

net/mlx5: Fix uninitialized variable bug in outlen_write()

[ Upstream commit 3d9e9b991670f728f22901b08808cd1732bb5964 ]

If sscanf() return 0, outlen is uninitialized and used in kzalloc(),
this is unexpected. We should return -EINVAL if the string is invalid.

Fixes: ffaf2c1a3989 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>