linux-phytec-ti

clk: keystone: Add new driver to handle syscon based clock

On TI's K2 and K3 SoCs, certain clocks can be gated/ungated by setting a
single bit in SoC's System Control Module registers. Sometime more than
one clock control can be in the same register.
Add driver to support such clocks. Registers that control clocks will be
grouped into a syscon regmap. Clock provider node will be child of the
syscon node.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Andrew F. Davis <afd@ti.com>