ext4: make ext4_ind_map_blocks work with fiemap

ext4: make ext4_ind_map_blocks work with fiemap

For indirect block mapping if the i_block > max supported block in inode
then ext4_ind_map_blocks() returns a -EIO error. But in case of fiemap
this could be a valid query to ->iomap_begin call.
So check if the offset >= s_bitmap_maxbytes in ext4_iomap_begin_report(),
then simply skip calling ext4_map_blocks().

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/87fa0ddc5967fa707656212a3b66a7233425325c.1582880246.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>