of: batterydata: add a kernel log if battery data is loaded

Add a single pr_info line to the of_batterydata load function
to print out what batterydata is loaded, if any. This will help
debug batterydata issues where it's difficult to tell what is the
currently loaded battery profile.

Change-Id: Ieeda37f82c09f9778d34ebad7cac7885e71cd64a
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>