clk: tegra: emc: Support multiple RAM codes

The timings parser doesn't append timings, but instead it parses only
the first timing and hence doesn't store all of the timings when
device-tree has timings for multiple RAM codes. In a result EMC scaling
doesn't work if timings are missing.

Tested-by: Steev Klimaszewski <steev@kali.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>