clk: iproc: define Broadcom iProc clock binding

Document the device tree binding for Broadcom iProc architecture based
clock controller

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
clk: iproc: add initial common clock support

This adds basic and generic support for various iProc PLLs and clocks
including the ARMPLL, GENPLL, LCPLL, MIPIPLL, and ASIU clocks.

SoCs under the iProc architecture can define their specific register
offsets and clock parameters for their PLL and clock controllers. These
parameters can be passed as arugments into the generic iProc PLL and
clock setup functions

Derived from code originally provided by Jonathan Richardson
<jonathar@broadcom.com>

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
clk: cygnus: add clock support for Broadcom Cygnus

The Broadcom Cygnus SoC is architected under the iProc architecture. It
has the following PLLs: ARMPLL, GENPLL, LCPLL0, MIPIPLL, all dervied
from an onboard crystal. Cygnus also has various ASIU clocks that are
derived directly from the onboard crystal.

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
ARM: dts: enable clock support for Broadcom Cygnus

Replace current device tree dummy clocks with real clock support for
Broadcom Cygnus SoC

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbraden@broadcom.com>