'struct thermal_zone_device_ops' are not modified in this driver.

Constifying these structures moves some data to a read-only section, so
increases overall security, especially when the structure holds some
function pointers.

On a x86_64, with allmodconfig:
Before:
======
   text	   data	    bss	    dec	    hex	filename
   2912	   1064	      0	   3976	    f88	drivers/net/ethernet/chelsio/cxgb4/cxgb4_thermal.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
   3040	    936	      0	   3976	    f88	drivers/net/ethernet/chelsio/cxgb4/cxgb4_thermal.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
Compile tested only
---
 drivers/net/ethernet/chelsio/cxgb4/cxgb4_thermal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_thermal.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_thermal.c
index b08356060fb4..7bab8da8f6e6 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_thermal.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_thermal.c
@@ -29,7 +29,7 @@ static int cxgb4_thermal_get_temp(struct thermal_zone_device *tzdev,
 	return 0;
 }
 
-static struct thermal_zone_device_ops cxgb4_thermal_ops = {
+static const struct thermal_zone_device_ops cxgb4_thermal_ops = {
 	.get_temp = cxgb4_thermal_get_temp,
 };
 
-- 
2.49.0