drivers/net: Move a dereference below a NULL test

If the NULL test is necessary, then the dereference should be moved below
the NULL test.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
type T;
expression E,E1;
identifier i,fld;
statement S;
@@

- T i = E->fld;
+ T i;
  ... when != E=E1
      when != i
  if (E == NULL||...) S
+ i = E->fld;
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/bnx2x_link.c

@@ -4212,13 +4212,14 @@ static void bnx2x_turn_off_sf(struct bnx2x *bp, u8 port)
 u8 bnx2x_get_ext_phy_fw_version(struct link_params *params, u8 driver_loaded,
 			      u8 *version, u16 len)
 {
-	struct bnx2x *bp = params->bp;
+	struct bnx2x *bp;
 	u32 ext_phy_type = 0;
 	u32 spirom_ver = 0;
 	u8 status = 0 ;
 
 	if (version == NULL || params == NULL)
 		return -EINVAL;
+	bp = params->bp;
 
 	spirom_ver = REG_RD(bp, params->shmem_base +
 		   offsetof(struct shmem_region,