This formats all copyright comments according to SPDX formatting guidelines.
Additionally, this resolves the remaining GPLv2 only licensed files by relicensing them to GPLv2.0-or-later.

It became apparent that logging can continuously spam errors that trigger file flushing.
Since committing the files to disk is an expensive operation, this causes unnecessarily high disk usage.
As such, we will revert Flush() to the previous behavior and add a Commit() member function in the event that this behavior is needed.

This ensures that GetSize always retrieves the correct file size after a write operation.

This check was preventing files with the Write or Append file access modes from being created, as per the documented behavior in FileAccessMode.
This amends the check to test for the existence of a filesystem object prior to checking whether it is a regular file.
Thanks to liushuyu for pointing out that removing the check altogether would not guard against attempting to open non-regular files such as directories, symlinks, FIFO (pipes), sockets, block devices, or character devices.
The documentation has also been updated for these functions to clarify that a file refers to a regular file.

fsp_srv: Fix filesystem access logging

The Append open mode will create a new file if said file does not exist at a given path, making this call redundant.