Remove unavailable and EOLed target boards - Ambiq (mbed-ce#290)

Author: Jamie Smith

.github/pull_request_template.md

@@ -51,11 +51,4 @@
  [] Tests / results supplied as part of this PR
 
 
-----------------------------------------------------------------------------------------------------------------
-### Reviewers <!-- Optional -->
-
-<!--
- Request additional reviewers with @username or @team
--->
-
 ----------------------------------------------------------------------------------------------------------------

targets/TARGET_Ambiq_Micro/TARGET_Apollo3/CMakeLists.txt

@@ -10,8 +10,6 @@ add_subdirectory(TARGET_SFE_ARTEMIS_DK EXCLUDE_FROM_ALL)
 add_subdirectory(TARGET_SFE_ARTEMIS_MODULE EXCLUDE_FROM_ALL)
 add_subdirectory(TARGET_SFE_ARTEMIS_NANO EXCLUDE_FROM_ALL)
 add_subdirectory(TARGET_SFE_ARTEMIS_THING_PLUS EXCLUDE_FROM_ALL)
-add_subdirectory(TARGET_SFE_EDGE EXCLUDE_FROM_ALL)
-add_subdirectory(TARGET_SFE_EDGE2 EXCLUDE_FROM_ALL)
 
 add_library(mbed-apollo3 INTERFACE)