soc/amd/picasso: Add support for 64bit builds

Tested on google/vilboz (running the PCI rom with yabel).

Change-Id: Icd72c4eef7805aacba6378632cbac7de9527673b
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63727
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>
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 5c16c29..503de3b 100644
--- a/src/soc/amd/common/block/cpu/noncar/pre_c.S
+++ b/src/soc/amd/common/block/cpu/noncar/pre_c.S
@@ -25,6 +25,10 @@
 bootblock_pre_c_entry:
 	post_code(0xa0)
 
+#if ENV_X86_64
+	#include <cpu/x86/64bit/entry64.inc>
+#endif
+
 	/* Clear .bss section */
 	cld
 	xor	%eax, %eax
@@ -40,10 +44,17 @@
 	and	$0xfffffff0, %esp
 	sub	$8, %esp
 
+#if ENV_X86_64
+	movd	%mm2, %rdi
+	shlq	$32, %rdi
+	movd	%mm1, %rsi
+	or	%rsi, %rdi
+#else
 	movd	%mm2, %eax
 	pushl	%eax		/* tsc[63:32] */
 	movd	%mm1, %eax
 	pushl	%eax		/* tsc[31:0] */
+#endif
 
 	post_code(0xa2)