video: vga16fb: Only probe for EGA and VGA 16 color graphic cards

video: vga16fb: Only probe for EGA and VGA 16 color graphic cards

The vga16fb framebuffer driver only supports Enhanced Graphics Adapter
(EGA) and Video Graphics Array (VGA) 16 color graphic cards.

But it doesn't check if the adapter is one of those or if a VGA16 mode
is used. This means that the driver will be probed even if a VESA BIOS
Extensions (VBE) or Graphics Output Protocol (GOP) interface is used.

This issue has been present for a long time but it was only exposed by
commit 443600efbc0f ("drivers/firmware: move x86 Generic System
Framebuffers support") since the platform device registration to match
the {vesa,efi}fb drivers is done later as a consequence of that change.

All non-x86 architectures though treat orig_video_isVGA as a boolean so
only do the supported video mode check for x86 and not for other arches.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=215001
Fixes: 443600efbc0f ("drivers/firmware: move x86 Generic System Framebuffers support")
Reported-by: Kris Karas <bugs-a21@moonlit-rail.com>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Kris Karas <bugs-a21@moonlit-rail.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220110095625.278836-3-javierm@redhat.com