clk: bcm63xx-gate: fix last clock availability

In order to make the last clock available, maxbit has to be set to the
highest bit value plus 1.

Fixes: 1c099779 ("clk: add BCM63XX gated clock controller driver")
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Link: https://lore.kernel.org/r/20200609110846.4029620-1-noltari@gmail.com


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