soc/amd/sabrina: change MAX_CPUS to 8

The Sabrina APU has a maximum configuration of 4 physical cores with 2
threads each, so a total of 8 CPU cores.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I627ed78ffba6098726c9c8ec55b60665503240ea
Reviewed-on: https://review.coreboot.org/c/coreboot/+/65068
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/sabrina/Kconfig

@@ -235,7 +235,7 @@ config ECAM_MMCONF_BUS_NUMBER
 
 config MAX_CPUS
 	int
-	default 16
+	default 8
 	help
 	  Maximum number of threads the platform can have.
 

src/soc/amd/sabrina/cpu.c

@@ -19,7 +19,7 @@
 #include <soc/iomap.h>
 #include <types.h>
 
-_Static_assert(CONFIG_MAX_CPUS == 16, "Do not override MAX_CPUS. To reduce the number of "
+_Static_assert(CONFIG_MAX_CPUS == 8, "Do not override MAX_CPUS. To reduce the number of "
 	"available cores, use the downcore_mode and disable_smt devicetree settings instead.");
 
 /* MP and SMM loading initialization */