Add ThinkPad X270 coreboot port from Kat Inskip

Courtesy of Kat Inskip who ported this board.

Headphone output doesn't work at the moment, due to incorrect verb.
Intel VBT is also wrong. Both are taken from another board.

This will be amended later with the correct verb and VBT.

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

include/vendor.sh

@@ -79,6 +79,7 @@ ME11delta=""
 ME11pch=""
 ME11sku=""
 ME11version=""
+MEshrink=""
 ME_bin_hash=""
 MEclean=""
 MRC_bin_hash=""
@@ -278,6 +279,15 @@ extract_intel_me()
 	x_ rm -f "$_metmp" "$xbtmp/a"
 	x_ rm -Rf "$_7ztest"
 
+	# maintain compatibility with older configs
+	# because in the past, shrink was assumed
+	if [ -z "$MEshrink" ]; then
+		MEshrink="y"
+	fi
+	if [ "$MEshrink" != "y" ] && [ "$MEshrink" != "n" ]; then
+		err "MEshrink set badly on '$board' vendor config"
+	fi
+
 	if [ "$ME11bootguard" = "y" ]; then
 		mfs="--whitelist MFS"
 
@@ -327,10 +337,17 @@ find_me()
 		_r=""
 	fi
 
+	if [ "$MEshrink" != "y" ]; then
+		_r=""
+		_trunc=""
+		mfs=""
+	fi
+
 	if [ "$MEclean" = "n" ]; then
 		_keep="-k"
 		_pass="-p"
 		_trunc=""
+		# TODO: should we also blank mfs and _r here?
 	fi
 
 	if "$mecleaner" $mfs $_r $_keep $_pass $_trunc -O "$xbtmp/a" \