ACPI/cpuidle: remove unused "power" field from Cx state data

It has never been used for anything, and Linux 3.7 doesn't propagate
this information anymore.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
Konrad, on the pv-ops side it may be better to pass zero rather than
leaving the field completely uninitialized.

--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -935,7 +935,6 @@ static void set_cx(
     }
 
     cx->latency  = xen_cx->latency;
-    cx->power    = xen_cx->power;
     
     cx->target_residency = cx->latency * latency_factor;
     if ( cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 )
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -96,7 +96,6 @@ static const struct cpuidle_state {
 	char		name[16];
 	unsigned int	flags;
 	unsigned int	exit_latency; /* in US */
-	int		power_usage; /* in mW */
 	unsigned int	target_residency; /* in US */
 } *cpuidle_state_table;
 
@@ -479,7 +478,6 @@ static int mwait_idle_cpu_init(struct no
 		cx->type = cstate;
 		cx->address = get_driver_data(cstate);
 		cx->entry_method = ACPI_CSTATE_EM_FFH;
-		cx->power = cpuidle_state_table[cstate].power_usage;
 		cx->latency = cpuidle_state_table[cstate].exit_latency;
 		cx->target_residency =
 			cpuidle_state_table[cstate].target_residency;
--- a/xen/include/xen/cpuidle.h
+++ b/xen/include/xen/cpuidle.h
@@ -46,7 +46,6 @@ struct acpi_processor_cx
     u32 address;
     u32 latency;
     u32 target_residency;
-    u32 power;
     u32 usage;
     u64 time;
 };