[msm] Enable battery charging flag based on power-on status

Determine power-on reason (e.g. due to USB cable connection,
button press, etc.) and pass androidboot.battchg_pause to kernel.

Enable flag on msm7627_* targets when power-on due to USB
cable connection.  This will trigger a pause during bootup
until user keypad input.

Change-Id: I7751d9d7bdd0e735cd5cdeeedb952879cb237005
diff --git a/target/init.c b/target/init.c
index 73fb2b3..a65a6ec 100644
--- a/target/init.c
+++ b/target/init.c
@@ -65,3 +65,8 @@
                  (unsigned enable, unsigned disconnect)
 {
 }
+
+__WEAK unsigned target_pause_for_battery_charge(void)
+{
+    return 0;
+}