arch/x86/cpu: Add define and strings for Hygon

Chengdu Haiguang IC Design Co., Ltd (Hygon) is a Joint Venture
between AMD and Haiguang Information Technology Co.,Ltd., aims
at providing high performance x86 processor for China server
market. Its first generation processor codename is Dhyana, which
originates from AMD technology and shares most of the architecture
with AMD's family 17h, but with different CPU Vendor ID ("HygonGenuine")
/Family series number (Family 18h).

More details can be found on:
http://lkml.kernel.org/r/5ce86123a7b9dad925ac583d88d2f921040e859b.1538583282.git.puwen@hygon.cn

Change-Id: I8af8b0f0675f978ac07522029696e43651a3153f
Signed-off-by: Jinke Fan <fanjinke@hygon.cn>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32876
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Lance Zhao <lance.zhao@gmail.com>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/arch/x86/cpu.c

@@ -113,6 +113,7 @@ static struct {
 	{ X86_VENDOR_TRANSMETA, "TransmetaCPU", },
 	{ X86_VENDOR_NSC,       "Geode by NSC", },
 	{ X86_VENDOR_SIS,       "SiS SiS SiS ", },
+	{ X86_VENDOR_HYGON,     "HygonGenuine", },
 };
 
 static const char *const x86_vendor_name[] = {
@@ -126,6 +127,7 @@ static const char *const x86_vendor_name[] = {
 	[X86_VENDOR_TRANSMETA] = "Transmeta",
 	[X86_VENDOR_NSC]       = "NSC",
 	[X86_VENDOR_SIS]       = "SiS",
+	[X86_VENDOR_HYGON]     = "Hygon",
 };
 
 static const char *cpu_vendor_name(int vendor)

src/arch/x86/include/arch/cpu.h

@@ -152,6 +152,7 @@ static inline unsigned int cpuid_edx(unsigned int op)
 #define X86_VENDOR_TRANSMETA  8
 #define X86_VENDOR_NSC        9
 #define X86_VENDOR_SIS       10
+#define X86_VENDOR_HYGON     11
 #define X86_VENDOR_ANY     0xfe
 #define X86_VENDOR_UNKNOWN 0xff