x86/srso: Add SRSO mitigation for Hygon processors

Add mitigation for the speculative return stack overflow vulnerability
which exists on Hygon processors too.

Signed-off-by: Pu Wen <puwen@hygon.cn>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/tencent_4A14812842F104E93AA722EC939483CEFF05@qq.com

Author: Pu Wen

arch/x86/kernel/cpu/common.c

@@ -1303,7 +1303,7 @@ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
 	VULNBL_AMD(0x15, RETBLEED),
 	VULNBL_AMD(0x16, RETBLEED),
 	VULNBL_AMD(0x17, RETBLEED | SMT_RSB | SRSO),
-	VULNBL_HYGON(0x18, RETBLEED | SMT_RSB),
+	VULNBL_HYGON(0x18, RETBLEED | SMT_RSB | SRSO),
 	VULNBL_AMD(0x19, SRSO),
 	{}
 };