x86: don't propagate acpi_skip_timer_override do Dom0

It's unclear why c/s 4850:923dd9975981 added this - Dom0 isn't
controlling the timer interrupt, and hence has no need to know.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/acpi/boot.c
+++ b/xen/arch/x86/acpi/boot.c
@@ -56,7 +56,9 @@ bool_t __initdata acpi_ht = 1;	/* enable
 bool_t __initdata acpi_lapic;
 bool_t __initdata acpi_ioapic;
 
-bool_t acpi_skip_timer_override __initdata;
+/* acpi_skip_timer_override: Skip IRQ0 overrides. */
+static bool_t acpi_skip_timer_override __initdata;
+boolean_param("acpi_skip_timer_override", acpi_skip_timer_override);
 
 #ifdef CONFIG_X86_LOCAL_APIC
 static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -71,10 +71,6 @@ static void parse_acpi_param(char *s);
 custom_param("acpi", parse_acpi_param);
 
 /* **** Linux config option: propagated to domain0. */
-/* acpi_skip_timer_override: Skip IRQ0 overrides. */
-boolean_param("acpi_skip_timer_override", acpi_skip_timer_override);
-
-/* **** Linux config option: propagated to domain0. */
 /* noapic: Disable IOAPIC setup. */
 boolean_param("noapic", skip_ioapic_setup);
 
@@ -1365,9 +1361,6 @@ void __init __start_xen(unsigned long mb
         /* Append any extra parameters. */
         if ( skip_ioapic_setup && !strstr(dom0_cmdline, "noapic") )
             safe_strcat(dom0_cmdline, " noapic");
-        if ( acpi_skip_timer_override &&
-             !strstr(dom0_cmdline, "acpi_skip_timer_override") )
-            safe_strcat(dom0_cmdline, " acpi_skip_timer_override");
         if ( (strlen(acpi_param) == 0) && acpi_disabled )
         {
             printk("ACPI is disabled, notifying Domain 0 (acpi=off)\n");
--- a/xen/include/asm-x86/acpi.h
+++ b/xen/include/asm-x86/acpi.h
@@ -80,7 +80,6 @@ int __acpi_release_global_lock(unsigned 
 
 extern bool_t acpi_lapic, acpi_ioapic, acpi_noirq;
 extern bool_t acpi_force, acpi_ht, acpi_disabled;
-extern bool_t acpi_skip_timer_override;
 extern u32 acpi_smi_cmd;
 extern u8 acpi_enable_value, acpi_disable_value;
 void acpi_pic_sci_set_trigger(unsigned int, u16);