arch/x86,cpu/x86: Move cpu_info initialization instructions into macro

This will help reduce duplication and make it easier to add new members
to the cpu_info struct.

BUG=b:194391185, b:179699789
TEST=Compare assembly of romstage and ramstage before and after

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: I31f264f4bb8b605fa3cb3bfff0d9bf79224072aa
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57859
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>

src/arch/x86/assembly_entry.S

@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <cpu/x86/cpu_info.S.inc>
 #include <rules.h>
 
 /*
@@ -35,13 +36,7 @@ _start:
 	/* reset stack pointer to CAR/EARLYRAM stack */
 	mov	$_STACK_TOP, %esp
 
-#if CONFIG(COOP_MULTITASKING)
-	/* Push the thread pointer. */
-	push	$0
-#endif
-	/* Push the CPU index and struct CPU */
-	push	$0
-	push	$0
+	push_cpu_info
 
 	/* clear .bss section as it is not shared */
 	cld

src/arch/x86/c_start.S

@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <cpu/x86/cpu_info.S.inc>
 #include <cpu/x86/post_code.h>
 #include <arch/ram_segs.h>
 
@@ -76,13 +77,7 @@ _start:
 	movl	$_estack, %esp
 	andl	$(~(CONFIG_STACK_SIZE-1)), %esp
 
-#if CONFIG(COOP_MULTITASKING)
-	/* Push the thread pointer. */
-	push	$0
-#endif
-	/* Push the CPU index and struct CPU */
-	push	$0
-	push	$0
+	push_cpu_info
 
 	/*
 	 *	Now we are finished. Memory is up, data is copied and

src/cpu/x86/cpu_info.S.inc

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/* Push struct cpu_info */
+.macro push_cpu_info index=$0
+#if CONFIG(COOP_MULTITASKING)
+	push	$0	/* *thread */
+#endif
+	push	\index	/* index */
+	push	$0	/* *cpu */
+.endm