[PATCH] Support for igfx on Celeron(R) 2957U (thanks Lorenzo Bivens)

> After some tinkering I managed to get igfx working on this device.
> hw cursor works.
> The only caveat is that I can only get video over hdmi...
> will revisit displayport later

lib/vgadb

@@ -437,6 +437,8 @@ ctlr
 	vid=0x8086 did=0x2a42	# Intel 4 Series Mobile
 	vid=0x8086 did=0x0a16	# Intel 4th Gen Core (HD 4400)
 	vid=0x8086 did=0x0412	# Intel 4th Gen Core (HD 4600)
+	vid=0x8086 did=0x3185	# Intel 9.5th Gen Core (UHD 600)
+	vid=0x8086 did=0x0a06
 	link=vga
 	hwgc=igfxhwgc
 	ctlr=igfx linear=1

sys/src/9/pc/vgaigfx.c

@@ -149,6 +149,7 @@ igfxcurregs(VGAscr* scr, int pipe)
 	switch(scr->pci->did){
 	case 0x0412:	/* Haswell HD Graphics 4600 */
 	case 0x0a16:	/* Haswell HD Graphics 4400 */
+	case 0x0a06:
 		if(pipe > 3)
 			return nil;
 		if(pipe == 3)

sys/src/cmd/aux/vga/igfx.c

@@ -366,6 +366,8 @@ devtype(Igfx *igfx)
 	case 0x0a16:	/* HD 4400 - 4th Gen Core (ULT) */
 		igfx->isult = 1;
 		/* wet floor */
+	case 0x0a06:
+	case 0x3185:    /* UHD 600 - 9.5 Gen Core */
 	case 0x0412:	/* HD 4600 - 4th Gen Core */
 		return TypeHSW;
 	case 0x0166:	/* 3rd Gen Core - ThinkPad X230 */