clk: bcm: Add clocks for Stingray SOC

This patch adds support for Stingray clocks in iproc
ccf. The Stingray SOC has various plls based on iproc
pll architecture.

Signed-off-by: Sandeep Tripathy <sandeep.tripathy@broadcom.com>
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>