clk: mediatek: mt7623: define id_offs_map and import clk ID from upstream

Define id_offs_map and use clk ID form upstream linux kernel to have a
1:1 match for the TOPCKGEN clock and permit usage of OF_UPSTREAM with
upstream dtsi.

For all the gate clock, the clk ID starts from 1 instead of zero. Define
an additional clock tree for them and set the .gates_offs to 1 to
account for this.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>