k7ddrphy: fix write_latency and take care of OSERDESE2 latency on oe
k7ddrphy: add ODELAYE2 on dm path to match dq path (ODELAYE2 even configure with a delay of 0 generates a delay)
k7ddrphy: set bitslip to 0 on ISERDESE2 (needed at least for sim)
k7ddrphy: fix read_latency (CL is 2 sys_clk since we use quarter rate)