clk: sunxi-ng: a64: stop force-selecting PLL-MIPI as TCON0 parent

clk: sunxi-ng: a64: stop force-selecting PLL-MIPI as TCON0 parent

Stop force-selecting PLL-MIPI as TCON0 parent, since it breaks video
output on Pinebook that uses RGB to eDP bridge.

Partially revert commit ca1170b69968 ("clk: sunxi-ng: a64: force
select PLL_MIPI in TCON0 mux"), while still leaving
CLK_SET_RATE_NO_REPARENT flag set, since we do not want the clock to
be reparented.

The issue is that apparently different TCON0 outputs require a different
clock, or the mux might be selecting the output type.

I did an experiment: I manually configured PLL_MIPI and PLL_VIDEO0_2X
to the same clock rate and flipped the switch with devmem. Experiment
clearly showed that whenever PLL_MIPI is selected as TCON0 clock parent,
the video output stops working.

Therefore, TCON0 clock parent corresponding to the output type must be
assigned in the device tree.

Fixes: ca1170b69968 ("clk: sunxi-ng: a64: force select PLL_MIPI in TCON0 mux")
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Frank Oltmanns <frank@oltmanns.dev> # on PinePhone
Tested-by: Stuart Gathman <stuart@gathman.org> # on OG Pinebook
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Link: https://patch.msgid.link/20250104074035.1611136-5-anarsoul@gmail.com
Signed-off-by: Chen-Yu Tsai <wens@csie.org>