Revert "PCI: brcmstb: Add mechanism to turn on subdev regulators"

Revert "PCI: brcmstb: Add mechanism to turn on subdev regulators"

This reverts commit 67211aadcb4b968d0fdc57bc27240fa71500c2d4.

This is part of a revert of the following commits:

  11ed8b8624b8 ("PCI: brcmstb: Do not turn off WOL regulators on suspend")
  93e41f3fca3d ("PCI: brcmstb: Add control of subdevice voltage regulators")
  67211aadcb4b ("PCI: brcmstb: Add mechanism to turn on subdev regulators")
  830aa6f29f07 ("PCI: brcmstb: Split brcm_pcie_setup() into two funcs")

Cyril reported that 830aa6f29f07 ("PCI: brcmstb: Split brcm_pcie_setup()
into two funcs"), which appeared in v5.17-rc1, broke booting on the
Raspberry Pi Compute Module 4.  Apparently 830aa6f29f07 panics with an
Asynchronous SError Interrupt, and after further commits here is a black
screen on HDMI and no output on the serial console.

This does not seem to affect the Raspberry Pi 4 B.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=215925
Link: https://lore.kernel.org/r/20220511201856.808690-4-helgaas@kernel.org
Reported-by: Cyril Brulebois <kibi@debian.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>