linuxkpi: add pci_is_vga()

[denis.borovikov_gmail.com]

Summary

Returns true for a VGA-compatible display controller and for the pre-PCI 2.0 VGA class (base 0x00, subclass 0x01), as Linux's pci_is_vga() does. LinuxKPI keeps only the base class in pdev->class, so the subclass comes from pci_get_subclass(), using the native class constants as linuxkpi_pci_map_rom() does. Used by drm/virtio to decide whether to remove the firmware framebuffer on virtio-vga.

Test Plan

Built on main with this applied: linuxkpi, linuxkpi_wlan, mlx5, iwlwifi and ath10k for aarch64 and amd64, and drm-kmod's virtio-gpu (freebsd/drm-kmod#517) without its interim copy. drm-kmod's identical interim copy runs at virtio-gpu attach on 16.0-CURRENT aarch64 under UTM.

[denis.borovikov_gmail.com]

Used by freebsd/drm-kmod#517

[wulf]

sys/compat/linuxkpi/common/include/linux/pci.h

420

Than we should fix lkpifill_pci_dev() and/or use native FreeBSD code. See e.g. linuxkpi_pci_map_rom() for example

[denis.borovikov_gmail.com]

native code, as wulf asked; pci_ids.h is no longer touched.

[denis.borovikov_gmail.com]

sys/compat/linuxkpi/common/include/linux/pci.h

420

Switched to native code, like linuxkpi_pci_map_rom(): pdev->class plus pci_get_subclass() against PCIC_DISPLAY/PCIS_DISPLAY_VGA and PCIC_OLD/PCIS_OLD_VGA. That also drops the pci_ids.h change.