soc/amd/picasso: add mb_pre_fspm() definition and weak implementation

On newer AMD platforms, mb_pre_fspm() is used to set GPIOs in romstage
for PCIe reset (currently set in bootblock) and touchscreen power
sequencing (not yet implemented, but will be later in the patch train).

Change-Id: Ia422aaa9e80355f9a9f8f850368441e5c8ff6598
Signed-off-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69452
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Reviewed-by: Jason Glenesk <jason.glenesk@amd.corp-partner.google.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/picasso/fsp_m_params.c

@@ -5,6 +5,7 @@
 #include <console/uart.h>
 #include <device/device.h>
 #include <fsp/api.h>
+#include <soc/platform_descriptors.h>
 #include <soc/pci_devs.h>
 #include <soc/fsp.h>
 #include <types.h>
@@ -12,6 +13,8 @@
 
 void __weak mainboard_updm_update(FSP_M_CONFIG *mupd) {}
 
+void __weak mb_pre_fspm(void) {}
+
 void platform_fsp_memory_init_params_cb(FSPM_UPD *mupd, uint32_t version)
 {
 	FSP_M_CONFIG *mcfg = &mupd->FspmConfig;
@@ -69,4 +72,5 @@ void platform_fsp_memory_init_params_cb(FSPM_UPD *mupd, uint32_t version)
 	mcfg->pspp_policy = config->pspp_policy;
 
 	mainboard_updm_update(mcfg);
+	mb_pre_fspm();
 }

src/soc/amd/picasso/include/soc/platform_descriptors.h

@@ -27,4 +27,6 @@ void mainboard_get_dxio_ddi_descriptors(
 		const fsp_dxio_descriptor **dxio_descs, size_t *dxio_num,
 		const fsp_ddi_descriptor **ddi_descs, size_t *ddi_num);
 
+void mb_pre_fspm(void);
+
 #endif /* AMD_PICASSO_PLATFORM_DESCRIPTORS_H */