bnx2x: Make BP_VF more robust

Prevent dereference of pointer in case it's NULL.
Signed-off-by: NYuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: NAriel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.h

@@ -299,7 +299,8 @@ struct bnx2x_vfdb {
 #define BP_VFDB(bp)		((bp)->vfdb)
 	/* vf array */
 	struct bnx2x_virtf	*vfs;
-#define BP_VF(bp, idx)		(&((bp)->vfdb->vfs[idx]))
+#define BP_VF(bp, idx)		((BP_VFDB(bp) && (bp)->vfdb->vfs) ? \
+					&((bp)->vfdb->vfs[idx]) : NULL)
 #define bnx2x_vf(bp, idx, var)	((bp)->vfdb->vfs[idx].var)
 
 	/* queue array - for all vfs */