drm/tegra: sor: No need to free devm_ allocated memory

Memory for the brick clock is allocated by devm_kzalloc(), so there is
no need here to free it explicitly.

The only function that calls tegra_clk_sor_brick_register() is the probe
function and it correctly checks and handles the return value, which, on
failure, will cause devm_ allocated memory to be freed automatically.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Thierry Reding <treding@nvidia.com>