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/picasso/Kconfig b/src/soc/amd/picasso/Kconfig
index 7f56803..765ac4c 100644
--- a/src/soc/amd/picasso/Kconfig
+++ b/src/soc/amd/picasso/Kconfig
@@ -75,6 +75,7 @@
 	select USE_FSP_NOTIFY_PHASE_END_OF_FIRMWARE
 	select X86_AMD_FIXED_MTRRS
 	select X86_INIT_NEED_1_SIPI
+	select HAVE_EXP_X86_64_SUPPORT
 
 config CHIPSET_DEVICETREE
 	string