arch/x86: Remove most C_ENV_BOOTBLOCK_SIZE limits

With top-aligned bootblock this is no longer globally needed.
The default maximum is now a generous 256 KiB with couple
platforms having lower limits of 32 KiB and 64 KiB.

Change-Id: Ib1aee44908c0dcbc17978d3ee53bd05a6200410c
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47600
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/src/mainboard/emulation/qemu-i440fx/Kconfig b/src/mainboard/emulation/qemu-i440fx/Kconfig
index 1b61871..9b990ce 100644
--- a/src/mainboard/emulation/qemu-i440fx/Kconfig
+++ b/src/mainboard/emulation/qemu-i440fx/Kconfig
@@ -76,7 +76,7 @@
 
 config C_ENV_BOOTBLOCK_SIZE
 	hex
-	default 0x4000
+	default 0x10000
 
 config DCACHE_BSP_STACK_SIZE
 	hex