Raspberry Pi's firmware offers an interface though which update it's
clock's frequencies. This is specially useful in order to change the CPU
clock (pllb_arm) which is 'owned' by the firmware and we're unable to
scale using the register interface provided by clk-bcm2835.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>