mount: optimize mountinfo traversal by decoupling device discovery

mount: optimize mountinfo traversal by decoupling device discovery

In mount_load_proc_self_mountinfo(), device_found_node() is synchronously called
during the traversal of mountinfo entries. When there are a large number of
mount points, and the device types are not significantly different, this results
in excessive time consumption during device discovery, causing a performance
bottleneck. This issue is particularly prominent on servers with a large number
of cores in IDC.

This patch decouples device discovery from the mountinfo traversal process,
avoiding redundant device operations. As a result, it significantly improves
performance, especially in environments with numerous mount points.

Signed-off-by: Chen Guanqiao <chen.chenchacha@foxmail.com>