x86, msr: Remove incorrect, duplicated code in the MSR driver

The MSR driver would compute the values for cpu and c at declaration,
and then again in the body of the function.  This isn't merely
redundant, but unsafe, since cpu might not refer to a valid CPU at
that point.

Remove the unnecessary and dangerous references in the declarations.
This code now matches the equivalent code in the CPUID driver.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/msr.c

@@ -172,11 +172,10 @@ static long msr_ioctl(struct file *file, unsigned int ioc, unsigned long arg)
 
 static int msr_open(struct inode *inode, struct file *file)
 {
-	unsigned int cpu = iminor(file->f_path.dentry->d_inode);
-	struct cpuinfo_x86 *c = &cpu_data(cpu);
+	unsigned int cpu;
+	struct cpuinfo_x86 *c;
 
 	cpu = iminor(file->f_path.dentry->d_inode);
-
 	if (cpu >= nr_cpu_ids || !cpu_online(cpu))
 		return -ENXIO;	/* No such CPU */