RK3588 EVB1 WLAN support

The EVB1 has an onboard PCIe based WLAN module named AP6275P, which is based on a Broadcom WLAN module. The PCIe device it only detectable when the RTC (hym8563) clock is kept enabled, since that is used by the WLAN/BT module and the necessary GPIOs are toggled correctly. Even then it takes some time for the module to become available. The vendor kernel from Rockchip solved this with a custom rfkill driver combined with some hacks in the PCIe driver.

In the upstream mailinglist there is currently a patchset prepared by Bartosz Golaszewski, who is working on a similar issue with a Qualcomm based design: https://lore.kernel.org/all/20240104130123.37115-1-brgl@bgdev.pl/ . Once this series has landed a driver for the AP6275P power sequence can be added and no hacks in the PCIe driver should be needed.

In addition to the power sequence, upstream's brcmfmac WLAN driver does not yet support the WLAN IP inside of the AP6275P module.