bnx2x: move global variable load_count to bnx2x.h

This will allow access to this global variable (used in no-mcp
mode) from different object files.

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>