!272 [openEuler-1.0-LTS] Add MWAIT Cx support for Zhaoxin CPUs.

Merge Pull Request from: @leoliu-oc 
 
When the processor is idle，low-power idle states (C-states) can be used to save power. For Zhaoxin processors，there are two methods to enter idle states. One is HLT instruction and legacy method of I/O reads from the CPI-defined register (known as P_LVLx)，the other one is MWAIT instruction with idle states hints.

Default for legacy operating system，HLT and P_LVLx I/O reads are used for Zhaoxin Processors to enter idle states, but we have checked on some Zhaoxin platform that MWAIT instruction is more efficient than P_LVLx I/O reads and HLT, so we add MWAIT Cx support for Zhaoxin Processors.

### Issue
https://gitee.com/openeuler/kernel/issues/I62TOM

### Test
N/A

### Known Issue
N/A

### Default config change
N/A

 
 
Link:https://gitee.com/openeuler/kernel/pulls/272 
Reviewed-by: Laibin Qiu <qiulaibin@huawei.com> 
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> 

arch/x86/include/asm/acpi.h

@@ -107,7 +107,8 @@ static inline bool arch_has_acpi_pdc(void)
 {
 	struct cpuinfo_x86 *c = &cpu_data(0);
 	return (c->x86_vendor == X86_VENDOR_INTEL ||
-		c->x86_vendor == X86_VENDOR_CENTAUR);
+			c->x86_vendor == X86_VENDOR_CENTAUR ||
+			c->x86_vendor == X86_VENDOR_ZHAOXIN);
 }
 
 static inline void arch_acpi_set_pdc_bits(u32 *buf)

arch/x86/kernel/acpi/cstate.c

@@ -195,7 +195,9 @@ static int __init ffh_cstate_init(void)
 	struct cpuinfo_x86 *c = &boot_cpu_data;
 
 	if (c->x86_vendor != X86_VENDOR_INTEL &&
-	    c->x86_vendor != X86_VENDOR_AMD)
+		c->x86_vendor != X86_VENDOR_AMD &&
+		c->x86_vendor != X86_VENDOR_CENTAUR &&
+		c->x86_vendor != X86_VENDOR_ZHAOXIN)
 		return -1;
 
 	cpu_cstate_entry = alloc_percpu(struct cstate_entry);