dt-bindings: clock: Add gcc_sec_ctrl_clk_src clock ID

The gcc_sec_ctrl_clk_src clock is required to be controlled by the
secure controller driver.

Signed-off-by: Taniya Das <tdas@codeaurora.org>
Link: https://lkml.kernel.org/r/1589709861-27580-3-git-send-email-tdas@codeaurora.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>