bnx2x: semi-Semantic changes

This patch includes a few changes that change the driver's flow without truly
changing anything in its functionality - use usleep_range for short sleeps
instead of msleep and initialize Tx consumer during initialization for better
information during errors.

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>