HID: hid-magicmouse: Increase evdev buffer size

The evdev buffer isn't big enough when you get many fingers on the
device. Bump up the buffer to a reasonable size, matching what other
multitouch devices use. Without this change, events may be discarded in
the evdev buffer before they are read.

Reported-by: Simon Budig <simon@budig.de>
Cc: Henrik Rydberg <rydberg@euromail.se>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: stable@kernel.org
Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
Acked-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>