f2fs-tools: add HAVE_PREAD and HAVE_PWRITE This patch will enable pread and pwrite support on Android platform. Signed-off-by: LongPing Wei <[email protected]> Reviewed-by: Chao Yu <[email protected]> Reviewed-by: Sheng Yong <[email protected]> Signed-off-by: Jaegeuk Kim <[email protected]>