minui: Skip EV_REL input devices.

This is causing recovery to skip real input devices on some
samsung phones where sensors are registered as input devices.
So there more then 16 of them. (ex. ks01lte)
And EV_REL input devices already disabled in recovery ui.cpp if
BOARD_RECOVERY_NEEDS_REL_INPUT is not set. So do same here not to exceed
the limit of MAX_DEVICES

Change-Id: If3d6e29d00229278a8ef3dfa445393c9f3d5f361