clk: rockchip: associate SCLK_MAC_PLL and disable reparenting on rk3036

The emac needs constant and very specific rate but the possible PLL-sources
are very limited, so we expect the PLL source to be set manually on per
board and don't want it to get changed in an automatic way later.
So add the necessary clock-id and disable reparenting on set_rate calls.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: linux-clk@vger.kernel.org

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: David S. Miller <davem@davemloft.net>