apollolake: Define MAX_CPUS at SoC scope

The three Intel Apollo Lake boards (apl_rvp, leafhill and minnow3) do
not define MAX_CPUS, which would then default to 1. Since this is most
likely an oversight, use the same value as other Apollo Lake boards.

To ensure this does not happen again, factor out MAX_CPUS to SoC scope.

Change-Id: I5ed98a6b592c8010b59eca7ff773ae1ccc4cd7b1
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45144
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/reef/Kconfig b/src/mainboard/google/reef/Kconfig
index de4df62..76a8640 100644
--- a/src/mainboard/google/reef/Kconfig
+++ b/src/mainboard/google/reef/Kconfig
@@ -81,10 +81,6 @@
 	default "Google_Coral" if BOARD_GOOGLE_CORAL
 	default "Google_Reef"
 
-config MAX_CPUS
-	int
-	default 4
-
 config UART_FOR_CONSOLE
 	int
 	default 2
diff --git a/src/mainboard/siemens/mc_apl1/Kconfig b/src/mainboard/siemens/mc_apl1/Kconfig
index 705351f..ac85670 100644
--- a/src/mainboard/siemens/mc_apl1/Kconfig
+++ b/src/mainboard/siemens/mc_apl1/Kconfig
@@ -40,8 +40,4 @@
 config UART_FOR_CONSOLE
 	default 2
 
-config MAX_CPUS
-	int
-	default 4
-
 endif # BOARD_SIEMENS_BASEBOARD_MC_APL1
diff --git a/src/mainboard/up/squared/Kconfig b/src/mainboard/up/squared/Kconfig
index 836c5bb..25e751c 100644
--- a/src/mainboard/up/squared/Kconfig
+++ b/src/mainboard/up/squared/Kconfig
@@ -60,10 +60,6 @@
 	string
 	default "10ec,8168"
 
-config MAX_CPUS
-	int
-	default 4
-
 config LINUX_COMMAND_LINE
 	string
 	default "console=ttyS4,115200 earlyprintk=ttyS4,115200,keep" if PAYLOAD_LINUXBOOT && UART_FOR_CONSOLE=0
diff --git a/src/soc/intel/apollolake/Kconfig b/src/soc/intel/apollolake/Kconfig
index f5d9323..a30333b 100644
--- a/src/soc/intel/apollolake/Kconfig
+++ b/src/soc/intel/apollolake/Kconfig
@@ -110,7 +110,7 @@
 
 config MAX_CPUS
 	int
-	default 4 if SOC_INTEL_GEMINILAKE
+	default 4
 
 config CHROMEOS
 	select CHROMEOS_RAMOOPS_DYNAMIC