ext4: use unsigned int for es_status values

Don't use an unsigned long long for the es_status flags; this requires
that we pass 64-bit values around which is painful on 32-bit systems.
Instead pass the extent status flags around using the low 4 bits of an
unsigned int, and shift them into place when we are reading or writing
es_pblk.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>