soc/amd/picasso: Correct processor ACPI scope

Change namespace from _PR to _SB.

Cq-Depend: chrome-internal:3208104
BUG=b:153242529
TEST=Boot a trembyle with change applied and dump SSDTs to ensure
processors are in _SB scope.

Change-Id: I534f02dc50756759da945cf64d5b3623b0ec9db1
Signed-off-by: Jason Glenesk <jason.glenesk@amd.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44325
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/picasso/Kconfig b/src/soc/amd/picasso/Kconfig
index 526900a..8001b7a 100644
--- a/src/soc/amd/picasso/Kconfig
+++ b/src/soc/amd/picasso/Kconfig
@@ -321,7 +321,7 @@
 
 config ACPI_CPU_STRING
 	string
-	default "\\_PR.C%03d"
+	default "\\_SB.C%03d"
 
 config ACPI_BERT
 	bool "Build ACPI BERT Table"