clk: tegra: Remove last remains of TEGRA210_CLK_SOR1_SRC

Later SoC generations implement this clock as SOR1_OUT. For consistency,
the Tegra210 implementation was adapted to match the same name in commit
4d1dc401 ("dt-bindings: clock: tegra: Add sor1_out clock").

Clean up the remaining pieces by adopting the new name for the internal
identifiers and remove the old alias. Note that since both SOR1_SRC and
SOR1_OUT were referring to the same device tree clock ID, this does not
break device tree ABI.

Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>