PCI/VGA: Move vgaarb to drivers/pci

The VGA arbiter is really PCI-specific and doesn't depend on any GPU
things.  Move it to the PCI subsystem.

Note that misc_init() must be called before vga_arb_device_init().  These
are both subsys_initcalls, so this ordering depends on the link order,
which is determined by drivers/Makefile:

  obj-y += pci/
  obj-y += char/        <-- misc_init()
  obj-y += gpu/         <-- vga_arb_device_init() (before this commit)

The drivers/pci/ subsys_initcalls are called *before* misc_init(), so
convert vga_arb_device_init() to subsys_initcall_sync(), which is called
after *all* subsys_initcalls.

Link: https://lore.kernel.org/r/20220224224753.297579-2-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/gpu/vga/Kconfig

@@ -1,23 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-config VGA_ARB
-	bool "VGA Arbitration" if EXPERT
-	default y
-	depends on (PCI && !S390)
-	help
-	  Some "legacy" VGA devices implemented on PCI typically have the same
-	  hard-decoded addresses as they did on ISA. When multiple PCI devices
-	  are accessed at same time they need some kind of coordination. Please
-	  see Documentation/gpu/vgaarbiter.rst for more details. Select this to
-	  enable VGA arbiter.
-
-config VGA_ARB_MAX_GPUS
-	int "Maximum number of GPUs"
-	default 16
-	depends on VGA_ARB
-	help
-	  Reserves space in the kernel to maintain resource locking for
-	  multiple GPUS.  The overhead for each GPU is very small.
-
 config VGA_SWITCHEROO
 	bool "Laptop Hybrid Graphics - GPU switching support"
 	depends on X86

drivers/gpu/vga/Makefile

@@ -1,3 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_VGA_ARB)  += vgaarb.o
 obj-$(CONFIG_VGA_SWITCHEROO) += vga_switcheroo.o