feat(st-ddr): add read valid training support

Add the read data eye training = training for optimal read valid placement
(RVTRN) when the built-in calibration is executed for LPDDR2 and LPDDR3.

Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
Change-Id: I7ac1c77c21ebc30315b532741f2f255c2312d5b2
2 files changed