HID: wacom: Fix HID_WACOM self-dependency

This patch fixes a silly mistake: HID_WACOM was dependent on HID_WACOM, so
the option wasn't showing up after make menuconfig

Signed-off-by: Przemo Firszt <przemo@firszt.eu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>