mb/intel/d510mo/Kconfig: Don't override CBFS_SIZE

There is no need to override CBFS_SIZE since there is no additional
firmware needed on the flash.

Also due to it having a description CBFS_SIZE was displayed twice in
menuconfig, which is fixed by this.

Change-Id: I1a8e2e458ac4d420f3fd4628c2805b6d4e2ee529
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/19331
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
diff --git a/src/mainboard/intel/d510mo/Kconfig b/src/mainboard/intel/d510mo/Kconfig
index 7131b3a..757a24c 100644
--- a/src/mainboard/intel/d510mo/Kconfig
+++ b/src/mainboard/intel/d510mo/Kconfig
@@ -36,10 +36,6 @@
 	hex
 	default 0xe0000000
 
-config CBFS_SIZE
-	hex "Size of CBFS filesystem in ROM"
-	default 0x100000
-
 config MAINBOARD_DIR
 	string
 	default intel/d510mo