p1am-100: remove duplicate build tags

targets/p1am-100.json

@@ -1,6 +1,6 @@
 {
     "inherits": ["atsamd21g18a"],
-    "build-tags": ["sam", "atsamd21g18a", "p1am_100"],
+    "build-tags": ["p1am_100"],
     "flash-command": "bossac -d -i -e -w -v -R --port={port} --offset=0x2000 {bin}",
     "flash-1200-bps-reset": "true"
 }