Use stdint.h instead

This commit replaces `u_int32_t`, `u64`, and `u_int64_t` with `uint32_t`
and `uint64_t` defined in C99 <stdint.h>.

Test: cd system/extras/f2fs_utils && mma
Change-Id: I56fd994d94103b3bc416543fbb6fad8b77c503f4
2 files changed