soc/amd/common/psp: move buffer sizes to common header

Since the P2C_BUFFER_MAXSIZE value will be needed in another compilation
unit, move the define to the common psp_def.h. P2C_BUFFER_MAXSIZE is
moved there too for consistency reasons.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I8d4d93760c90ad6e0ecadf70600b1d697a02fa82
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83701
Reviewed-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/common/block/psp/psp_def.h

@@ -108,6 +108,9 @@ struct mbox_cmd_dtpm_config_buffer {
 #define PSP_INIT_TIMEOUT 10000 /* 10 seconds */
 #define PSP_CMD_TIMEOUT 1000 /* 1 second */
 
+#define C2P_BUFFER_MAXSIZE 0xc00 /* Core-to-PSP buffer */
+#define P2C_BUFFER_MAXSIZE 0xc00 /* PSP-to-core buffer */
+
 uintptr_t get_psp_mmio_base(void);
 
 void psp_print_cmd_status(int cmd_status, struct mbox_buffer_header *header);

src/soc/amd/common/block/psp/psp_smm.c

@@ -11,9 +11,6 @@
 
 #include "psp_def.h"
 
-#define C2P_BUFFER_MAXSIZE 0xc00 /* Core-to-PSP buffer */
-#define P2C_BUFFER_MAXSIZE 0xc00 /* PSP-to-core buffer */
-
 /*
  * When sending PSP mailbox commands to the PSP from the SMI handler after the boot done
  * command was sent, the corresponding data buffer needs to be placed in this core to PSP (C2P)