This patch changes all references to ELECOM trackballs using their
series name to refer to them by their model name.

ELECOM provides multiple series of mice such as EX-G, HUGE, and DEFT.
Although it has not caused conflicts in the driver, there can be more
than one iteration of mice in each series. For example, there are 7
variants of EX-G trackballs but only three (M-XT3URBK, M-XT3DRBK, and
M-XT4DRBK) need a driver to work correctly.

There are also 4 DEFT series trackballs but two of them have the same
VID:PID as the other two. I picked the earlier model for the naming of
the PID macros.
Signed-off-by: NTomasz Kramkowski <tk@the-tk.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>