soc/amd/mendocino/psp_verstage/svc: Fix reset_system type

The size of the input parameter to RESET_SYSTEM svc call is expected to
be 4 bytes. Fix the reset_system type from enum to uint32_t.

BUG=b:243476183
TEST=Build and boot to OS in Skyrim with PSP verstage. Trigger a system
reset to ensure that the system is reset successfully.

Change-Id: I6319a1dfc89602722c1c2b1c4ee744493ae8b33f
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/67117
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/mendocino/psp_verstage/svc.h

@@ -107,7 +107,7 @@ struct cmd_param_delay_in_micro_second {
 };
 
 struct cmd_param_reset_system {
-	enum reset_type reset_type;
+	uint32_t reset_type;
 };
 
 struct cmd_param_get_boot_mode {