HID: wacom: Lazy-init batteries

Rather than creating batteries as part of the initial device probe, let's
make the process lazy. This gives us the opportunity to prevent batteries
from being created in situations where they are unnecessary.

There are two cases in particular where batteries are being unnecessarily
created at initialization. These are AES sensors (for which we don't know
any battery status information until a battery-powered pen actually comes
into prox) peripheral tablets which share HID descriptors between the
wired-only and wireless-capable SKUs of a family of devices.

This patch will delay battery initialization of the former until a pen
actually comes into prox. It will delay battery initialization of the
latter until either a pen comes into prox or a "heartbeat" packet is
processed.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217062
Link: https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues/2354


Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Tested-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>