bnx2x: Fixed a compilation warning

bnx2x_src_init_t2() is used only when BCM_CNIC is defined.
So, to avoid a compilation warning, we won't define it unless
BCM_CNIC is defined.

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>