clk: tegra: emc: Avoid out-of-bounds bug

Apparently there was an attempt to avoid out-of-bounds accesses when there
is only one memory timing available, but there is a typo in the code that
neglects that attempt.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>