Kconfig: Move defaults for CBFS_SIZE

We want the question for CBFS size to be next to the rom size in the
mainboard directory, but that doesn't seem to work for how people
want to set the defaults.  Instead of having the list of exceptions
to the size, just set the defaults at the end of kconfig.

- Move the defaults for chipsets not setting HAVE_INTEL_FIRMWARE into
the chipset Kconfigs (gm45, nehalem, sandybridge, x4x)
- Override the default for HAVE_INTEL_FIRMWARE on skylake.
- Move the HAVE_INTEL_FIRMWARE default setting into the firmware
Kconfig file
- Move the location of the default CBFS_SIZE=ROM_SIZE to the end of
the top level kconfig file, while leaving the question where it is.

Test=rebuild Kconfig files before and after the change, verify that
they are how they were intended to be.

Note: the Skylake boards actually changed value, because they were
picking up the 0x100000 from HAVE_INTEL_FIRMWARE instead of the
0x200000 desired.  This was due to the SOC_INTEL_SKYLAKE being after
the HAVE_INTEL_FIRMWARE default.  Affected boards were:
Google chell, glados, & lars and Intel kunimitsu.

Change-Id: I2963a7a7eab037955558d401f5573533674a664f
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/13645
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
diff --git a/src/northbridge/intel/gm45/Kconfig b/src/northbridge/intel/gm45/Kconfig
index 98ce644..6ee6558 100644
--- a/src/northbridge/intel/gm45/Kconfig
+++ b/src/northbridge/intel/gm45/Kconfig
@@ -27,6 +27,10 @@
 	select INTEL_EDID
 	select INTEL_GMA_ACPI
 
+config CBFS_SIZE
+	hex
+	default 0x100000
+
 config BOOTBLOCK_NORTHBRIDGE_INIT
 	string
 	default "northbridge/intel/gm45/bootblock.c"