fs/jbd2: Fix the documentation of the jbd2_write_superblock() callers

Commit 2a222ca9 ("fs: have submit_bh users pass in op and flags
separately") renamed the jbd2_write_superblock() 'write_op' argument into
'write_flags'. Propagate this change to the jbd2_write_superblock()
callers. Additionally, change the type of 'write_flags' into blk_opf_t.

Cc: Mike Christie <michael.christie@oracle.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-57-bvanassche@acm.org


Signed-off-by: Jens Axboe <axboe@kernel.dk>