hw/misc/sga: Remove the deprecated "sga" device

It's been deprecated since QEMU v6.2, so it should be OK to
finally remove this now.

Message-Id: <20230209161540.1054669-1-thuth@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

pc-bios/README

@@ -20,12 +20,6 @@
   -machine pseries,x-vof=on. When enabled, the firmware acts as a slim shim and
   QEMU implements parts of the IEEE 1275 Open Firmware interface.
 
-- sgabios (the Serial Graphics Adapter option ROM) provides a means for
-  legacy x86 software to communicate with an attached serial console as
-  if a video card were attached.  The master sources reside in a subversion
-  repository at http://sgabios.googlecode.com/svn/trunk.  A git mirror is
-  available at https://gitlab.com/qemu-project/sgabios.git.
-
 - The PXE roms come from the iPXE project. Built with BANNER_TIME 0.
   Sources available at http://ipxe.org.  Vendor:Device ID -> ROM mapping:
 

pc-bios/meson.build

@@ -28,7 +28,6 @@ blobs = [
   'bios-256k.bin',
   'bios-microvm.bin',
   'qboot.rom',
-  'sgabios.bin',
   'vgabios.bin',
   'vgabios-cirrus.bin',
   'vgabios-stdvga.bin',