lguest: fix crash lguest_time_init

fe25c7fc2e "x86: lguest: Convert to new irq chip functions" converted
enable_lguest_irq() to take a struct irq_data *, but didn't fix the one
internal caller.

Signed-off-by: Rusty Russell <[e-mail]>
To: [e-mail]

arch/x86/lguest/boot.c

···
 	clockevents_register_device(&lguest_clockevent);
 
 	/* Finally, we unblock the timer interrupt. */
-	enable_lguest_irq(0);
+	clear_bit(0, lguest_data.blocked_interrupts);
 }
 
 /*