Fix build error in blkid/tst_types.c when using diet libc

Fix build error in blkid/tst_types.c when using diet libc

When compiling with diet libc, <sys/types.h> must be included in order
to define the types used in asm/types.h.  Strange choice, but
workable.  This doesn't cause much problems for e2fsprogs except
blkid/tst_types.h, which needed a #include of <sys/types.h>.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>