gradius3: remove KONAMI_ROM_DEINTERLEAVE and some no longer needed code (nw)

k051960, k052109: remove m_dx and m_dy, already nonfunctional since devicefication.
These chips don't have variable offsets like the later Konami customs do
(Gradius 3 title screen being offset 2 pixels to the left is a BTANB, see MT #4118)