char: ipmi: constify bmc_dev_attr_group and bmc_device_type

File size before:
   text	   data	    bss	    dec	    hex	filename
  25678	   1024	     92	  26794	   68aa	drivers/char/ipmi/ipmi_msghandler.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
  25806	    896	     92	  26794	   68aa	drivers/char/ipmi/ipmi_msghandler.o

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/ipmi_msghandler.c

@@ -2397,7 +2397,7 @@ static umode_t bmc_dev_attr_is_visible(struct kobject *kobj,
 	return mode;
 }
 
-static struct attribute_group bmc_dev_attr_group = {
+static const struct attribute_group bmc_dev_attr_group = {
 	.attrs		= bmc_dev_attrs,
 	.is_visible	= bmc_dev_attr_is_visible,
 };
@@ -2407,7 +2407,7 @@ static const struct attribute_group *bmc_dev_attr_groups[] = {
 	NULL
 };
 
-static struct device_type bmc_device_type = {
+static const struct device_type bmc_device_type = {
 	.groups		= bmc_dev_attr_groups,
 };