xfs: fix file_path handling in tracepoints

Since file_path() takes the output buffer as one of its arguments, we
might as well have it format directly into the tracepoint's char array
instead of wasting stack space.

Fixes: 3934e8eb ("xfs: create a big array data structure")
Fixes: 5076a604

 ("xfs: support in-memory buffer cache targets")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202403290419.HPcyvqZu-lkp@intel.com/


Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>