lenovo/t440p: add a target with 4mb cbfs

this is exactly the same as the normal t440p config,
except that cbfs is 4mb instead of 8mb.

this is useful when externally updating libreboot,
or unbricking; it could also be used for lazier
installation, where you only flash the 2nd chip
without doing a disassembly to get at the other one,
if the user didn't care about neutering the ME.

Signed-off-by: Leah Rowe <leah@libreboot.org>

config/coreboot/t440plibremrc_4mcbfs_12mb/target.cfg

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+tree="default"
+xarch="i386-elf"
+payload_seabios="y"
+payload_grub="y"
+payload_memtest="y"
+grub_scan_disk="nvme ahci"
+grubtree="xhci"
+vcfg="haswell"
+build_depend="seabios/default grub/xhci memtest86plus u-boot/amd64coreboot"
+payload_uboot="amd64"