[M] Change in coreboot[master]: vc/amd/*,soc/amd/*: Add SVC call to get HSP Secure State

[Matt DeVillier (Code Review)]

Attention is currently required from: Jason Glenesk, Raul Rangel, Martin L Roth, Jon Murphy, Name of user not set #1004763, Martin Roth, Fred Reitberger, Karthik Ramasubramanian, Felix Held.

Matt DeVillier has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/71207 )

Change subject: vc/amd/*,soc/amd/*: Add SVC call to get HSP Secure State
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Patch Set 5:

(1 comment)

File src/vendorcode/amd/fsp/cezanne/include/bl_uapp/bl_syscall_public.h:

https://review.coreboot.org/c/coreboot/+/71207/comment/b7f49f6c_e0266909 
PS1, Line 362: uint32_t svc_get_hsp_secure_state(uint32_t *hsp_secure_state);
> What about declaring a default implementation weak in the common code that just returns an unimplemented status?  Then platforms that implement the call can override?  That's how we handle GPIO's in boards.

The problem with this approach IMO is that going forward, all platforms are likely to support this feature, so we'll be duplicating it in the SoC code. It might be better to have a default weak implementation of the actual function and then just override with w/noop for the older platforms as needed?