x86, lto: Finally enable gcc LTO for x86

Now that everything is in place, allow gcc LTO for the x86 build.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Martin Liska <mliska@suse.cz>
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6455d84..2c96fac 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -112,6 +112,7 @@
 	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
 	select ARCH_SUPPORTS_LTO_CLANG
 	select ARCH_SUPPORTS_LTO_CLANG_THIN
+	select ARCH_SUPPORTS_LTO_GCC
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_MEMTEST
 	select ARCH_USE_QUEUED_RWLOCKS