clk: mediatek: add array size fields to clk trees

clk: mediatek: add array size fields to clk trees

Add num_plls, num_fclks, num_fdivs, num_muxes, and num_gates fields to
the mtk_clk_tree struct and populate them in the clk trees for all
existing drivers.

Currently, there is no bounds checking when accessing the arrays in
the clk tree structs. Adding these fields will allow for bounds checking
in the future.

Signed-off-by: David Lechner <dlechner@baylibre.com>