bsp/tms570: Remove obsolete build option

Update #4982.

spec/build/bsps/arm/tms570/grp.yml

@@ -40,8 +40,6 @@ links:
   uid: optreginit
 - role: build-dependency
   uid: optscibaud
-- role: build-dependency
-  uid: opttms570ls3137
 - role: build-dependency
   uid: optlinkflags
 - role: build-dependency

spec/build/bsps/arm/tms570/opttms570ls3137.yml

@@ -1,16 +0,0 @@
-SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
-actions:
-- get-boolean: null
-- define-condition: null
-build-type: option
-copyrights:
-- Copyright (C) 2020 embedded brains GmbH & Co. KG
-default:
-- enabled-by: true
-  value: false
-description: |
-  target used for identify TMS570LS3137 board
-enabled-by: true
-links: []
-name: ARM_TMS570LS3137
-type: build