power: supply: qti_battery_charger: Handle probe failure gracefully

Due to a race condition between the probe and glink message
callback, it is observed that the glink messages/notifications
can be handled even after the probe failure which leads to
an invalid memory access. Fix it by introducing "initialized"
flag. While at it, add few error logs to identify the exact
message failures.

Change-Id: I18e61dea734efde6a11ee072793da8eead269b12
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>