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/system.c b/drivers/acpi/system.c
index c3bb7faa..d86dcb3 100644
--- a/drivers/acpi/system.c
+++ b/drivers/acpi/system.c
@@ -57,7 +57,7 @@
 	return single_open(file, acpi_system_read_info, PDE(inode)->data);
 }
 
-static struct file_operations acpi_system_info_ops = {
+static const struct file_operations acpi_system_info_ops = {
 	.open = acpi_system_info_open_fs,
 	.read = seq_read,
 	.llseek = seq_lseek,
@@ -67,7 +67,7 @@
 static ssize_t acpi_system_read_dsdt(struct file *, char __user *, size_t,
 				     loff_t *);
 
-static struct file_operations acpi_system_dsdt_ops = {
+static const struct file_operations acpi_system_dsdt_ops = {
 	.read = acpi_system_read_dsdt,
 };
 
@@ -94,7 +94,7 @@
 static ssize_t acpi_system_read_fadt(struct file *, char __user *, size_t,
 				     loff_t *);
 
-static struct file_operations acpi_system_fadt_ops = {
+static const struct file_operations acpi_system_fadt_ops = {
 	.read = acpi_system_read_fadt,
 };