newisys: Remove mainboard directory and Kconfig files

Since there are no longer any newisys mainboards, remove the directory
and Kconfig files.  This removes the Kconfig warning:

mainboard/newisys/Kconfig:3:warning: config symbol defined without type

Change-Id: Icb2e782173166a26fa261f6cfb81b665a846931e
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: http://review.coreboot.org/12423
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/mainboard/newisys/Kconfig

@@ -1,16 +0,0 @@
-if VENDOR_NEWISYS
-
-choice
-	prompt "Mainboard model"
-
-source "src/mainboard/newisys/*/Kconfig.name"
-
-endchoice
-
-source "src/mainboard/newisys/*/Kconfig"
-
-config MAINBOARD_VENDOR
-	string
-	default "Newisys"
-
-endif # VENDOR_NEWISYS

src/mainboard/newisys/Kconfig.name

@@ -1,2 +0,0 @@
-config VENDOR_NEWISYS
-	bool "Newisys"