clk: mediatek: mt7981: replace infracfg ID with upstream linux

Replace infracfg clk ID with upstream linux version.

Add some missing clk for PWM3 and for PCIe. The same format is used here
with the factor first, then mux and then gates.

To correctly reference the gates in clk_gate function, define the
gates_offs value in clk_tree now that they are at an offset from mux and
factor.

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