crypto/ccp: hoist kernel part of SNP_PLATFORM_STATUS

crypto/ccp: hoist kernel part of SNP_PLATFORM_STATUS

...to its own function. This way it can be used when the kernel needs
access to the platform status regardless of the INIT state of the firmware.

No functional change intended.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Tycho Andersen (AMD) <tycho@kernel.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Tycho Andersen (AMD) <tycho@kernel.org>
Link: https://patch.msgid.link/20260416232329.3408497-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>