ACPI: add 'const' to several ACPI file_operations

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/fan.c b/drivers/acpi/fan.c
index daed246..045c894 100644
--- a/drivers/acpi/fan.c
+++ b/drivers/acpi/fan.c
@@ -120,7 +120,7 @@
 	return count;
 }
 
-static struct file_operations acpi_fan_state_ops = {
+static const struct file_operations acpi_fan_state_ops = {
 	.open = acpi_fan_state_open_fs,
 	.read = seq_read,
 	.write = acpi_fan_write_state,