lenovo: Use readable name as part number.

Part number is used only for coreboot ROM identification and
in coreboot tables. Rather than guessing the P/N, just use readable name.

SMBIOS uses information from EEPROM and so isn't affected.

Change-Id: I33534c3acb83f20d5b493c82bfc98896bf64ff1a
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/7177
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins)
diff --git a/src/mainboard/lenovo/x200/Kconfig b/src/mainboard/lenovo/x200/Kconfig
index 6939f5e..aeeded5 100644
--- a/src/mainboard/lenovo/x200/Kconfig
+++ b/src/mainboard/lenovo/x200/Kconfig
@@ -28,7 +28,7 @@
 
 config MAINBOARD_PART_NUMBER
 	string
-	default "7458CY9"
+	default "ThinkPad X200"
 
 config MAINBOARD_VENDOR
 	string