ram: rk3399: Handle data training return types

ram: rk3399: Handle data training return types

data trainings calls like ca, wl, rg, rl, wdql have proper
return types with -EIO and the return type missed to handle
in data_training function.

This patch, add proper return type checks along with useful
debug statement on each data training calls.

Incidentally this would help to prevent the sdram initialization
hang for single channel dram and when the code is trying to
initialize second channel with proper return type of relevant
data training call might failed.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <Kever.yang@rock-chips.com>