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>
diff --git a/src/arch/x86/cpu.c b/src/arch/x86/cpu.c
index e6c9435..cfab219 100644
--- a/src/arch/x86/cpu.c
+++ b/src/arch/x86/cpu.c
@@ -113,6 +113,7 @@
 	{ 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 @@
 	[X86_VENDOR_TRANSMETA] = "Transmeta",
 	[X86_VENDOR_NSC]       = "NSC",
 	[X86_VENDOR_SIS]       = "SiS",
+	[X86_VENDOR_HYGON]     = "Hygon",
 };
 
 static const char *cpu_vendor_name(int vendor)