HID: magicmouse: Correct report range of major / minor axes

In patch "HID: magicmouse: Adjust major / minor axes to scale",
touch_major and touch_minor axes are scaled by a factor of
four when reported but the max touch_major/minor is not scaled
accordingly. This patch scales the max touch_major/minor to
be consistent with the reported value.

Signed-off-by: Yufeng Shen <miletus@chromium.org>
Acked-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>