hwmon: (adt7470) Fix busy-loop and I2C flooding in update thread

In the Linux kernel, the following vulnerability has been resolved:

vfio: Remove device debugfs before releasing devres

VFIO device debugfs files created with debugfscreatedevmseqfile() store a devres allocated debugfsdevmentry as inode private data. vfiounregistergroupdev() currently calls vfiodevicedel() before vfiodevicedebugfsexit(), but devicedel() releases devres. This can leave debugfs entries visible with stale inode private data while unregister waits for userspace references to drain.

Remove the per-device debugfs tree before vfiodevicedel(). The debugfs view is diagnostic only, so losing it at the start of unregister is preferable to preserving entries whose backing storage may already have been released.

Complete the teardown by clearing the per-device debugfs root after removal. This matches the global debugfs root cleanup and prevents future users from mistaking a removed dentry for a live debugfs tree during the remainder of unregister.