disable automatic loading of sgabios when -nographic

sgabios hasn't gotten a lot of coverage since it was not shipped.  For 1.0,
let's disable the automatic loading of the option ROM in -nographic
mode.  We can put it back for 1.1.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/pc.c

@@ -1103,15 +1103,6 @@ void pc_vga_init(PCIBus *pci_bus)
             isa_vga_init();
         }
     }
-
-    /*
-     * sga does not suppress normal vga output. So a machine can have both a
-     * vga card and sga manually enabled. Output will be seen on both.
-     * For nographic case, sga is enabled at all times
-     */
-    if (display_type == DT_NOGRAPHIC) {
-        isa_create_simple("sga");
-    }
 }
 
 static void cpu_request_exit(void *opaque, int irq, int level)