src: Introduce `ARCH_ALL_STAGES_X86`

Introduce the `ARCH_ALL_STAGES_X86` Kconfig symbol to automatically
select the per-stage arch options. Subsequent commits will leverage
this to allow choosing between 32-bit and 64-bit coreboot where all
stages are x86. AMD Picasso and AMD Cezanne are the only exceptions
to this rule: they disable `ARCH_ALL_STAGES_X86` and explicitly set
the per-stage arch options accordingly.

Change-Id: Ia2ddbae8c0dfb5301352d725032f6ebd370428c9
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55759
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
diff --git a/src/soc/amd/cezanne/Kconfig b/src/soc/amd/cezanne/Kconfig
index 78db12f..7dd3447 100644
--- a/src/soc/amd/cezanne/Kconfig
+++ b/src/soc/amd/cezanne/Kconfig
@@ -70,6 +70,9 @@
 	select X86_AMD_FIXED_MTRRS
 	select X86_AMD_INIT_SIPI
 
+config ARCH_ALL_STAGES_X86
+	default n
+
 config SOC_AMD_COMMON_BLOCK_UCODE_SIZE
 	default 5568
 
diff --git a/src/soc/amd/picasso/Kconfig b/src/soc/amd/picasso/Kconfig
index 44728a8..42c3bfc 100644
--- a/src/soc/amd/picasso/Kconfig
+++ b/src/soc/amd/picasso/Kconfig
@@ -69,6 +69,9 @@
 	select UDK_2017_BINDING
 	select HAVE_CF9_RESET
 
+config ARCH_ALL_STAGES_X86
+	default n
+
 config SOC_AMD_COMMON_BLOCK_UCODE_SIZE
 	default 3200
 
diff --git a/src/soc/amd/stoneyridge/Kconfig b/src/soc/amd/stoneyridge/Kconfig
index 0e80f14..821d1ee 100644
--- a/src/soc/amd/stoneyridge/Kconfig
+++ b/src/soc/amd/stoneyridge/Kconfig
@@ -10,7 +10,6 @@
 config CPU_SPECIFIC_OPTIONS
 	def_bool y
 	select ACPI_SOC_NVS
-	select ARCH_ALL_STAGES_X86_32
 	select ARCH_X86
 	select BOOT_DEVICE_SUPPORTS_WRITES if BOOT_DEVICE_SPI_FLASH
 	select COLLECT_TIMESTAMPS_NO_TSC