clk: mediatek: mt7988: drop 1/1 spurious factor for topckgen

clk: mediatek: mt7988: drop 1/1 spurious factor for topckgen

Now that we can have advanced parent handling for mux, we can drop
spurious topckgen 1/1 factor. This is in preparation to make the clk
ID match the ID in upstream include for mt7988.

Drop the factor entry from mt7988-clk.h and reference to them in
mt7988.dtsi. Muxes and gates are updated to reference the apmixed clk
following how it's done in upstream kernel linux. Add relevant clk type
flag in clk_tree for apmixed and topckgen.

Also move TOP_XTAL to the fixed clock table following how it's done in
upstream linux kernel.

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