infiniband: apply device filters before reading counters

[rafal-szypulka]

Summary

Apply the InfiniBand device include/exclude filter before reading device
attributes and counters.

The collector now:

1. obtains only the InfiniBand device names from procfs;
2. applies the configured device filter;
3. parses each accepted device individually.

Motivation

#3694 added:

• --collector.infiniband.device-include
• --collector.infiniband.device-exclude

However, the collector currently calls procfs.InfiniBandClass() before
applying the filter. InfiniBandClass() eagerly parses every device,
including all per-port counters. The filter therefore controls emitted
metrics but does not prevent reads from excluded devices.

On systems with restricted or Fabric Manager-managed Mellanox PFs, those
reads can trigger repeated mlx5_core ACCESS_REG(0x805) firmware errors even
when the device is excluded.

This change makes the flags perform filtering before any per-device reads,
which is necessary to address #3434.

Compatibility

With neither filter configured, all devices continue to be collected.

This depends on the new procfs device-listing and per-device parsing APIs.

Testing

The node_exporter and procfs branches were tested together using a Go
workspace and the collector test package cross-compiles successfully for
Linux.

Fixes #3434.