Revert "HID: wacom: generic: Send BTN_TOOL_PEN in prox once the pen enters range"

This reverts commit 3e70969e.

This commit causes a few problems for userspace. The most noteworthy are
problems related to the distinguishing of different pens and pointer jumps
when entering proximity. Userspace is written with the expectation that a
pen will provide its tool ID and serial number (if available) in the very
first in-prox report. By sending BTN_TOOL_PEN when the tablet starts
communicating rather than waiting until a tool ID/serial number is
available, userspace ends up treating all pens as being the same and
lacking a serial number. Similarly, userspace assumes that the first
report will contain X/Y data, but by marking the pen as being in-prox
without an X/Y coordinate, userspace ends up warping the pen to the last-
known X/Y location. As of commit 5b40104e ("HID: wacom: generic: Reset
events back to zero when pen leaves") this means warping to (0,0).

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>