cpu/x86/64bit: Turn jumping to long mode into a macro

This makes it easier to reuse, e.g. if you want to do it twice in one
assembly file.

Change-Id: Ida861338004187e4e714be41e17c8447fa4cf935
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79261
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/src/soc/amd/common/block/cpu/noncar/pre_c.S b/src/soc/amd/common/block/cpu/noncar/pre_c.S
index eb556fa..bb2203b 100644
--- a/src/soc/amd/common/block/cpu/noncar/pre_c.S
+++ b/src/soc/amd/common/block/cpu/noncar/pre_c.S
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <amdblocks/post_codes.h>
+#include <cpu/x86/64bit/entry64.inc>
 #include <cpu/x86/post_code.h>
 
 .section .init, "ax", @progbits
@@ -27,7 +28,7 @@
 	post_code(POSTCODE_BOOTBLOCK_PRE_C_ENTRY)
 
 #if ENV_X86_64
-	#include <cpu/x86/64bit/entry64.inc>
+	setup_longmode $(CONFIG_ARCH_X86_64_PGTBL_LOC)
 #endif
 
 	/* Clear .bss section */