bcachefs: Add tracepoints for bch2_sync_fs() and bch2_fsync()

Add trace_bch2_sync_fs() and trace_bch2_fsync() implementations.

The output in trace is as follows:
  sync-29779   [000] .....   193.700935: bch2_sync_fs: dev 254,16 wait 1
  <...>-40027  [002] .....   342.535227: bch2_fsync: dev 254,32 ino 4099 parent 4096 datasync 1

Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>