clk: bcm: rpi: Add ISP to exported clocks

The ISP clock can be controlled by the driver, so register it
with the clock subsystem.

Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://lore.kernel.org/r/20250116-bcm2712-clk-updates-v1-1-10bc92ffbf41@raspberrypi.com


Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>