Add lx106-hal submodule.

From https://github.com/tommie/lx106-hal

.gitmodules

@@ -2,3 +2,6 @@
 	path = crosstool-NG
 	url = https://github.com/jcmvbkbc/crosstool-NG
 	branch = lx106-g++
+[submodule "lx106-hal"]
+	path = lx106-hal
+	url = https://github.com/tommie/lx106-hal

lx106-hal

@@ -0,0 +1 @@
+Subproject commit 90cdf910a8431675b6814ba447550edca3a78d4c