net: thunderx: Reduce mbox wait response time.

Replace msleep() with usleep_range() as internally it uses hrtimers.
This will put a cap on maximum wait time.

Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>