sysclk: add atmosphere-libs as submodule

.gitmodules

@@ -7,3 +7,6 @@
 [submodule "Source/sys-clk/overlay/lib/libultrahand"]
 	path = Source/sys-clk/overlay/lib/libultrahand
 	url = https://github.com/ppkantorski/libultrahand
+[submodule "Source/sys-clk/sysmodule/lib/Atmosphere-libs"]
+	path = Source/sys-clk/sysmodule/lib/Atmosphere-libs
+	url = https://github.com/Atmosphere-NX/Atmosphere-libs.git