drm/nouveau/bios/dcb: accept "maxwell" lane count values for dcb 4.0

We previously assumed that the values "2" and "4" were new in DCB 4.1,
however, there's at least one GM107 DCB 4.0 board (Quadro K620) that
uses the newer values.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_bios.c

@@ -1481,19 +1481,18 @@ parse_dcb20_entry(struct drm_device *dev, struct dcb_table *dcb,
 			entry->dpconf.link_bw = 540000;
 			break;
 		}
-		entry->dpconf.link_nr = (conf & 0x0f000000) >> 24;
-		if (dcb->version < 0x41) {
-			switch (entry->dpconf.link_nr) {
-			case 0xf:
-				entry->dpconf.link_nr = 4;
-				break;
-			case 0x3:
-				entry->dpconf.link_nr = 2;
-				break;
-			default:
-				entry->dpconf.link_nr = 1;
-				break;
-			}
+		switch ((conf & 0x0f000000) >> 24) {
+		case 0xf:
+		case 0x4:
+			entry->dpconf.link_nr = 4;
+			break;
+		case 0x3:
+		case 0x2:
+			entry->dpconf.link_nr = 2;
+			break;
+		default:
+			entry->dpconf.link_nr = 1;
+			break;
 		}
 		link = entry->dpconf.sor.link;
 		entry->i2c_index += NV_I2C_AUX(0);

drivers/gpu/drm/nouveau/nvkm/subdev/bios/dcb.c

@@ -156,20 +156,19 @@ dcb_outp_parse(struct nvkm_bios *bios, u8 idx, u8 *ver, u8 *len,
 					break;
 				}
 
-				outp->dpconf.link_nr = (conf & 0x0f000000) >> 24;
-				if (*ver < 0x41) {
-					switch (outp->dpconf.link_nr) {
-					case 0x0f:
-						outp->dpconf.link_nr = 4;
-						break;
-					case 0x03:
-						outp->dpconf.link_nr = 2;
-						break;
-					case 0x01:
-					default:
-						outp->dpconf.link_nr = 1;
-						break;
-					}
+				switch ((conf & 0x0f000000) >> 24) {
+				case 0xf:
+				case 0x4:
+					outp->dpconf.link_nr = 4;
+					break;
+				case 0x3:
+				case 0x2:
+					outp->dpconf.link_nr = 2;
+					break;
+				case 0x1:
+				default:
+					outp->dpconf.link_nr = 1;
+					break;
 				}
 
 				/* fall-through... */