console: Simplify bootblock console Kconfig selection logic

Instead of depending BOOTBLOCK_CONSOLE on a set of architectures,
allow the arch or platform to specify whether it can provide a C
environment. This simplifies the selection logic.

Change-Id: Ia3e41796d9aea197cee0a073acce63761823c3aa
Signed-off-by: Alexandru Gagniuc <alexandrux.gagniuc@intel.com>
Reviewed-on: https://review.coreboot.org/12871
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/arch/arm/Kconfig

@@ -6,6 +6,7 @@ config ARCH_BOOTBLOCK_ARM
 	bool
 	default n
 	select ARCH_ARM
+	select C_ENVIRONMENT_BOOTBLOCK
 
 config ARCH_VERSTAGE_ARM
 	bool

src/arch/arm64/Kconfig

@@ -6,6 +6,7 @@ config ARCH_BOOTBLOCK_ARM64
 	bool
 	default n
 	select ARCH_ARM64
+	select C_ENVIRONMENT_BOOTBLOCK
 
 config ARCH_VERSTAGE_ARM64
 	bool

src/arch/mips/Kconfig

@@ -23,6 +23,7 @@ config ARCH_BOOTBLOCK_MIPS
 	default n
 	select ARCH_MIPS
 	select BOOTBLOCK_CUSTOM
+	select C_ENVIRONMENT_BOOTBLOCK
 
 config ARCH_VERSTAGE_MIPS
 	bool

src/arch/riscv/Kconfig

@@ -7,6 +7,7 @@ config ARCH_BOOTBLOCK_RISCV
 	default n
 	select ARCH_RISCV
 	select BOOTBLOCK_CUSTOM
+	select C_ENVIRONMENT_BOOTBLOCK
 
 config ARCH_VERSTAGE_RISCV
 	bool