mdadm: Replace obsolete usleep with nanosleep According to POSIX.1-2001, usleep is considered obsolete. Replace it with a wrapper that uses nanosleep, as recommended in man. Add handy macros for conversions between msec, usec and nsec. Signed-off-by: Mateusz Grzonka <mateusz.grzonka@intel.com> Signed-off-by: Jes Sorensen <jsorensen@fb.com>