platform/x86: msi-laptop: constify msipf*_attribute_group

File size before:
   text	   data	    bss	    dec	    hex	filename
   5396	   5016	     85	  10497	   2901	drivers/platform/x86/msi-laptop.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
   5524	   4888	     85	  10497	   2901	drivers/platform/x86/msi-laptop.o

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/msi-laptop.c

@@ -563,11 +563,11 @@ static struct attribute *msipf_old_attributes[] = {
 	NULL
 };
 
-static struct attribute_group msipf_attribute_group = {
+static const struct attribute_group msipf_attribute_group = {
 	.attrs = msipf_attributes
 };
 
-static struct attribute_group msipf_old_attribute_group = {
+static const struct attribute_group msipf_old_attribute_group = {
 	.attrs = msipf_old_attributes
 };