[platform] add platform check for core configuration option (#4008)

diff --git a/examples/platforms/cc2538/Makefile.am b/examples/platforms/cc2538/Makefile.am
index 8f95f2d..a7d2f00 100644
--- a/examples/platforms/cc2538/Makefile.am
+++ b/examples/platforms/cc2538/Makefile.am
@@ -44,6 +44,7 @@
     flash.c                                 \
     misc.c                                  \
     openthread-core-cc2538-config.h         \
+    openthread-core-cc2538-config-check.h   \
     platform-cc2538.h                       \
     radio.c                                 \
     rom-utility.h                           \