clk: cdce925: make regmap_cdce925_bus constant

clk: cdce925: make regmap_cdce925_bus constant

This struct is only used for the regmap initialization via
devm_regmap_init() (which expects a pointer to a const struct
regmap_bus, as it will not modify the struct), and it is not modified
after its declaration.

Move regmap_cdce925_bus to a read-only section.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20241001-clk-cdce925-regmap_bus-const-v1-1-49fc11555b04@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>