oprofile, x86: Simplify init/exit functions

Now, that we only call the exit function if init succeeds with commit:

 979048e1 oprofile: don't call arch exit code from init code on failure

we can simplify the x86 init/exit functions too. Variable using_nmi
becomes obsolete.
Signed-off-by: Robert Richter <robert.richter@amd.com>

arch/x86/oprofile/nmi_int.c

@@ -695,9 +695,6 @@ static int __init ppro_init(char **cpu_type)
 	return 1;
 }
 
-/* in order to get sysfs right */
-static int using_nmi;
-
 int __init op_nmi_init(struct oprofile_operations *ops)
 {
 	__u8 vendor = boot_cpu_data.x86_vendor;
@@ -705,8 +702,6 @@ int __init op_nmi_init(struct oprofile_operations *ops)
 	char *cpu_type = NULL;
 	int ret = 0;
 
-	using_nmi = 0;
-
 	if (!cpu_has_apic)
 		return -ENODEV;
 
@@ -790,13 +785,11 @@ int __init op_nmi_init(struct oprofile_operations *ops)
 	if (ret)
 		return ret;
 
-	using_nmi = 1;
 	printk(KERN_INFO "oprofile: using NMI interrupt.\n");
 	return 0;
 }
 
 void op_nmi_exit(void)
 {
-	if (using_nmi)
 	exit_sysfs();
 }