Kconfig: Drop the C_ENVIRONMENT_BOOTBLOCK symbol

The romcc bootblock will be deprecated soon and most platforms use
C_ENVIRONMENT_BOOTBLOCK already. This patch drops the
CONFIG_C_ENVIRONMENT_BOOTBLOCK symbol and adds CONFIG_ROMCC_BOOTBLOCK
where needed.

Change-Id: I773a76aade623303b7cd95ebe9b0411e5a7ecbaf
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37154
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Michał Żygowski <michal.zygowski@3mdeb.com>

src/Kconfig

@@ -1177,9 +1177,7 @@ config BOOTBLOCK_CUSTOM
 	# src/lib/bootblock.c#main() C entry point.
 	bool
 
-config C_ENVIRONMENT_BOOTBLOCK
-	# To be selected by arch or platform if a C environment is available during the
-	# bootblock. Normally this signifies availability of RW memory (e.g. SRAM).
+config ROMCC_BOOTBLOCK
 	bool
 
 ###############################################################################