UPSTREAM: clk: rockchip: add a factor clock type

UPSTREAM: clk: rockchip: add a factor clock type

Add a clock type for fixed factor clocks. This allows us to define fixed
factor clocks where they appear in the clock hierarchy instead of in the
init function.

The additional factor_gate type, finally allows us to model some last
parts of the clock tree correctly.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
(cherry picked from commit 29a30c269aba4223e2a8b443f443d7def1e43fea)

Change-Id: Ie4ec8b9d9199cdbe0be045c2ed4c270029e37949
Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>