clk: bcm2835: Allow custom CCF flags for the PLLs

While some clock types allow for each clock to specify its own custom
flags, the PLLs can't. We will need this for the PLLB, so let's add it.

Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/ae8bd505d8851f6646e244cd76b6b289346973c8.1592210452.git-series.maxime@cerno.tech


Signed-off-by: Stephen Boyd <sboyd@kernel.org>