board/km: move ls102xa boards to environment text files

Create a common.env which we can use later on also for other boards.

Signed-off-by: Holger Brunck <holger.brunck@hitachienergy.com>
diff --git a/board/keymile/pg-wcom-ls102xa/pg-wcom-seli8.env b/board/keymile/pg-wcom-ls102xa/pg-wcom-seli8.env
new file mode 100644
index 0000000..4031f8b
--- /dev/null
+++ b/board/keymile/pg-wcom-ls102xa/pg-wcom-seli8.env
@@ -0,0 +1,3 @@
+#include <environment/pg-wcom/ls102xa.env>
+
+hostname=SELI8