Built-in video card device fixes from selected machines, such as Tandy and Olivetti.

Added the Compaq Deskpro BIOS from 1987 (8086, not 386).
Added the Trident TVGA9000B video card and fixed some anomalies with the TVGA8900B.

src/machine/m_tandy.c

@@ -1192,6 +1192,12 @@ tandy1k_hx_get_device(void)
     return &vid_device_hx;
 }
 
+const device_t *
+tandy1k_sl_get_device(void)
+{
+    return &vid_device_sl;
+}
+
 
 static void
 eep_write(uint16_t addr, uint8_t val, void *priv)