clk: rockchip: remove more CLK_IGNORE_UNUSED for rk3399 clocktree

clk: rockchip: remove more CLK_IGNORE_UNUSED for rk3399 clocktree

Optimize rk3399 clocktree by removing CLK_IGNORE_UNUSED of some clocks.

clocks will managered by usb:
- clk_usbphy0_480m_src
- clk_usbphy1_480m_src
- clk_usbphy_480m

clocks will be managered by pvtm:
- clk_pvtm_core_l
- clk_pvtm_core_b
- clk_pvtm_ddr

clocks will be managered by dfi:
- pclk_ddr_mon
- clk_dfimon0_timer
- clk_dfimon1_timer
- aclk_dcf
- pclk_dcf

Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com>
(am from https://patchwork.kernel.org/patch/9410123/)

Change-Id: I9c32423cafde00fc47673638633ca0c884253f36
Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com>