ext4: journal_path mount options should follow links

Before the commit 461c3af0 ("ext4: Change handle_mount_opt() to use
fs_parameter") ext4 mount option journal_path did follow links in the
provided path.

Bring this behavior back by allowing to pass pathwalk flags to
fs_lookup_param().

Fixes: 461c3af0

 ("ext4: Change handle_mount_opt() to use fs_parameter")
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20221004135803.32283-1-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org