bnx2x: Protect code with NOMCP

Don't run code that can't be run if MCP is not present.
This will prevent NULL pointer dereferencing.

Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>