hwrng: amd - manage resource allocation

As amd driver doesn't bind to PCI device, we'd better manage reource
allocation on our own to disallow (possible) conflicts.

Signed-off-by: Dmitry Eremin-Solenikov <[e-mail]>
Acked-by: Matt Mackall <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/char/hw_random/amd-rng.c

···
 	pmbase &= 0x0000FF00;
 	if (pmbase == 0)
 		goto out;
+	if (!request_region(pmbase + 0xF0, 8, "AMD HWRNG")) {
+		dev_err(&pdev->dev, "AMD HWRNG region 0x%x already in use!\n",
+			pmbase + 0xF0);
+		err = -EBUSY;
+		goto out;
+	}
 	amd_rng.priv = (unsigned long)pmbase;
 	amd_pdev = pdev;
 
···
 	if (err) {
 		printk(KERN_ERR PFX "RNG registering failed (%d)\n",
 		       err);
+		release_region(pmbase + 0xF0, 8);
 		goto out;
 	}
 out:
···
 
 static void __exit mod_exit(void)
 {
+	u32 pmbase = (unsigned long)amd_rng.priv;
+	release_region(pmbase + 0xF0, 8);
 	hwrng_unregister(&amd_rng);
 }