FROMLIST: clk: rockchip: add clock flag parameter when register pll

FROMLIST: clk: rockchip: add clock flag parameter when register pll

add clock flag parameter so we can pass specific clock flag
(like CLK_GET_RATE_NOCACHE etc..)to pll driver.

Change-Id: I1e076b3efa6b5da082b6e68e2e2a4c9dfd93e3d4
Signed-off-by: Heiko Stübner <heiko@sntech.de>
Signed-off-by: Lin Huang <hl@rock-chips.com>