bnx2x: correct usleep_range usage

Change the incorrect usage of `usleep_range(1000, 1000)' into
`usleep_range(1000, 2000)'.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>