clk: meson: g12a: make VCLK2 and ENCL clock path configurable by CCF

clk: meson: g12a: make VCLK2 and ENCL clock path configurable by CCF

In order to setup the DSI clock, let's make the unused VCLK2 clock path
configuration via CCF.

The nocache option is removed from following clocks:
- vclk2_sel
- vclk2_input
- vclk2_div
- vclk2
- vclk_div1
- vclk2_div2_en
- vclk2_div4_en
- vclk2_div6_en
- vclk2_div12_en
- vclk2_div2
- vclk2_div4
- vclk2_div6
- vclk2_div12
- cts_encl_sel

vclk2 and vclk2_div uses the newly introduced vclk regmap driver
to handle the enable and reset bits.

In order to set a rate on cts_encl via the vclk2 clock path,
the NO_REPARENT flag is set on cts_encl_sel & vclk2_sel in order
to keep CCF from selection a parent.
The parents of cts_encl_sel & vclk2_sel are expected to be defined
in DT or manually set by the display driver at some point.

The following clock scheme is to be used for DSI:

xtal
\_ gp0_pll_dco
   \_ gp0_pll
      |- vclk2_sel
      |  \_ vclk2_input
      |     \_ vclk2_div
      |        \_ vclk2
      |           \_ vclk2_div1
      |              \_ cts_encl_sel
      |                 \_ cts_encl	-> to VPU LCD Encoder
      |- mipi_dsi_pxclk_sel
      \_ mipi_dsi_pxclk_div
         \_ mipi_dsi_pxclk		-> to DSI controller

The mipi_dsi_pxclk_div is set as bypass with a single /1 entry in div_table
in order to use the same GP0 for mipi_dsi_pxclk and vclk2_input.

The SET_RATE_PARENT is only set on the mipi_dsi_pxclk_sel clock so the
DSI bitclock is the reference base clock to calculate the vclk2_div value
when pixel clock is set on the cts_encl endpoint.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240403-amlogic-v6-4-upstream-dsi-ccf-vim3-v12-3-99ecdfdc87fc@linaro.org
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>