clk: rockchip: add clock-id for rk3036 emac pll source clock

Suitable PLLs for the emac on the rk3036 are difficult to find
and one of them is the (continuously changing) APLL. So in most
cases it will be necessary to select a PLL manually.
So add a clock-id for it.

Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Cc: Xing Zheng <zhengxing@rock-chips.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: linux-clk@vger.kernel.org
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: David S. Miller <davem@davemloft.net>