octeon_ep: poll for control messages

Poll for control messages until interrupts are enabled.
All the interrupts are enabled in ndo_open().
Add ability to listen for notifications from firmware before ndo_open().
Once interrupts are enabled, this polling is disabled and all the
messages are processed by bottom half of interrupt handler.

Signed-off-by: Veerasenareddy Burru <vburru@marvell.com>
Signed-off-by: Abhijit Ayarekar <aayarekar@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>