Removed unnecessary sys/types.h include

Likely included at some point for ssize_t, this is no longer needed and
causes some problems for embedded compilers.

Currently littlefs doesn't even use size_t/ssize_t in its definition of
lfs_size_t/lfs_ssize_t, so I don't think this will ever be required.

Found by LDong-Arm, vvn-git

lfs_util.h

@@ -23,7 +23,6 @@
 // System includes
 #include <stdint.h>
 #include <stdbool.h>
-#include <sys/types.h>
 #include <string.h>
 #include <inttypes.h>