f2fs-tools: Build f2fs-tools with _FILE_OFFSET_BITS=64

After commit b15b6cc56ac7("f2fs-tools: convert to lseek() and kill
lseek64"), 32-bit Android should also be built with
_FILE_OFFSET_BITS=64.

When calling the lseek function on arm32, if the offset exceeds 32
bits, lseek fails. Therefore, the flag _FILE_OFFSET_BITS=64 is
added to support operations with offsets greater than 32 bits on
arm32.

Signed-off-by: Xiuhong Wang <xiuhong.wang@unisoc.com>
Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>