jbd2: rename jbd_debug() to jbd2_debug()

The name of jbd_debug() is confusing as all functions inside jbd2 have
jbd2_ prefix. Rename jbd_debug() to jbd2_debug(). No functional changes.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Link: https://lore.kernel.org/r/20220608112355.4397-2-jack@suse.cz


Signed-off-by: Theodore Ts'o <tytso@mit.edu>