ext2: remove duplicate include

Remove linux/fiemap.h which is included more than once

Link: https://lore.kernel.org/r/20200819025434.65763-1-wanghai38@huawei.com


Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>