ext4: remove ext4_{ind,ext}_calc_metadata_amount()

ext4: remove ext4_{ind,ext}_calc_metadata_amount()

Remove the ext4_ind_calc_metadata_amount() and
ext4_ext_calc_metadata_amount() functions, which have been unused since
commit 499211196647 ("ext4: remove metadata reservation checks").

Also remove the i_da_metadata_calc_last_lblock and
i_da_metadata_calc_len fields from struct ext4_inode_info, as these were
only used by these removed functions.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20191231180444.46586-2-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>