Revert "PCI: brcmstb: Split brcm_pcie_setup() into two funcs"

Revert "PCI: brcmstb: Split brcm_pcie_setup() into two funcs"

This reverts commit 39cc3722e3d4434066edfb4246ef786ca941cc1d.

This is part of a revert of the following commits:

  9124fa69a5c5 ("PCI: brcmstb: Do not turn off WOL regulators on suspend")
  7392030db6aa ("PCI: brcmstb: Add control of subdevice voltage regulators")
  145289ca7118 ("PCI: brcmstb: Add mechanism to turn on subdev regulators")
  39cc3722e3d4 ("PCI: brcmstb: Split brcm_pcie_setup() into two funcs")

Cyril reported that 39cc3722e3d4 ("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 39cc3722e3d4 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/20220511201856.808690-5-helgaas@kernel.org
Reported-by: Cyril Brulebois <kibi@debian.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>