hwmon: (adt7475) constify attribute_group structures.

attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group. So mark the non-const structs as const.

File size before:
   text	   data	    bss	    dec	    hex	filename
  10055	   7032	      0	  17087	   42bf	drivers/hwmon/adt7475.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
  10567	   6520	      0	  17087	   42bf	drivers/hwmon/adt7475.o
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/adt7475.c

@@ -1319,14 +1319,14 @@ static struct attribute *vid_attrs[] = {
 	NULL
 };
 
-static struct attribute_group adt7475_attr_group = { .attrs = adt7475_attrs };
-static struct attribute_group fan4_attr_group = { .attrs = fan4_attrs };
-static struct attribute_group pwm2_attr_group = { .attrs = pwm2_attrs };
-static struct attribute_group in0_attr_group = { .attrs = in0_attrs };
-static struct attribute_group in3_attr_group = { .attrs = in3_attrs };
-static struct attribute_group in4_attr_group = { .attrs = in4_attrs };
-static struct attribute_group in5_attr_group = { .attrs = in5_attrs };
-static struct attribute_group vid_attr_group = { .attrs = vid_attrs };
+static const struct attribute_group adt7475_attr_group = { .attrs = adt7475_attrs };
+static const struct attribute_group fan4_attr_group = { .attrs = fan4_attrs };
+static const struct attribute_group pwm2_attr_group = { .attrs = pwm2_attrs };
+static const struct attribute_group in0_attr_group = { .attrs = in0_attrs };
+static const struct attribute_group in3_attr_group = { .attrs = in3_attrs };
+static const struct attribute_group in4_attr_group = { .attrs = in4_attrs };
+static const struct attribute_group in5_attr_group = { .attrs = in5_attrs };
+static const struct attribute_group vid_attr_group = { .attrs = vid_attrs };
 
 static int adt7475_detect(struct i2c_client *client,
 			  struct i2c_board_info *info)