clk: mediatek: reset: Merge and revise reset register function

clk: mediatek: reset: Merge and revise reset register function

There are two versions for clock reset register control for MediaTek
SoCs. The old hardware is one bit per reset control, and does not
have separate registers for bit set, clear and read-back operations.
This matches the scheme supported by the simple reset driver.

However, because we need to use different data structure from
reset_simple_data, we can not use the operation of simple reset
driver.
For this reason, we keep the original functions and name this version
as "MTK_RST_SIMPLE".

In this patch:
- Add a version enumeration to separate different reset hardware.
- Merge the reset register function of simple and set_clr into one
  function "mtk_register_reset_controller".
- Rename input variable "num_regs" to "rst_bank_nr" to avoid
  confusion. This variable is used to define the quantity of reset bank.
- Document mtk_reset_version and mtk_register_reset_controller.

Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20220523093346.28493-6-rex-bc.chen@mediatek.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>