x86: hpet: Fix copy-and-paste mistake in earlier change

This fixes an oversight in 396e2c6fed4ff13b53ce0e573105531cf53b0cad
("x86: Clear HPET configuration registers on startup"), noticed by
Thomas Gleixner.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/4FBF7DA902000078000861EE@nat28.tlf.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/hpet.c

@@ -870,7 +870,7 @@ int __init hpet_enable(void)
 	else
 		pr_warn("HPET initial state will not be saved\n");
 	cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY);
-	hpet_writel(cfg, HPET_Tn_CFG(i));
+	hpet_writel(cfg, HPET_CFG);
 	if (cfg)
 		pr_warn("HPET: Unrecognized bits %#x set in global cfg\n",
 			cfg);