fs: fix proc_handler for sysctl_nr_open

Use proc_douintvec_minmax() instead of proc_dointvec_minmax() to handle
sysctl_nr_open, because its data type is unsigned int, not int.

Fixes: 9b80a184 ("fs/file: more unsigned file descriptors")
Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
Link: https://lore.kernel.org/r/20241124034636.325337-1-alexjlzheng@tencent.com


Signed-off-by: Christian Brauner <brauner@kernel.org>