add kernel support for newer nvidia 6XXX series cards.

Reference: /n/sources/patch/applied/nvidia-kernel-update
Date: Sat Jul  9 02:57:14 CES 2005

--- /sys/src/9/pc/vganvidia.c	Sat Jul  9 02:49:03 2005
+++ /sys/src/9/pc/vganvidia.c	Sat Jul  9 02:48:55 2005
@@ -165,13 +165,9 @@
 	}
 
 	/* find video memory size */
-	if (scr->id & 0x0F00) {
-		q = KADDR(scr->io + Pfb +  0x020C);
-		tmp = (*q >> 20) & 0xFF;
-		if (tmp == 0)
-			tmp = 16;
-		scr->storage =  tmp*1024*1024;
-	} else {
+	switch (scr->id & 0x0ff0) {
+	case 0x0020:
+	case 0x00A0:
 		q = KADDR(scr->io + Pfb);
 		tmp = *q;
 		if (tmp & 0x0100) {
@@ -183,6 +179,24 @@
 			else
 				scr->storage = 1024*1024*32;
 		}
+		break;
+	case 0x01A0:
+		p = pcimatchtbdf(MKBUS(BusPCI, 0, 0, 1));
+		tmp = pcicfgr32(p, 0x7C);
+		scr->storage = (((tmp >> 6) & 31) + 1) * 1024 * 1024;
+		break;
+	case 0x01F0:
+		p = pcimatchtbdf(MKBUS(BusPCI, 0, 0, 1));
+		tmp = pcicfgr32(p, 0x84);
+		scr->storage = (((tmp >> 4) & 127) + 1) * 1024 * 1024;
+		break;
+	default:
+		q = KADDR(scr->io + Pfb +  0x020C);
+		tmp = (*q >> 20) & 0xFF;
+		if (tmp == 0)
+			tmp = 16;
+		scr->storage =  tmp*1024*1024;
+		break;
 	}
 }
 
@@ -209,10 +223,15 @@
 
 	vgaxo(Crtx, 0x31, vgaxi(Crtx, 0x31) & ~0x01);
 
-	if (scr->id & 0x0F00)
-		p = KADDR(scr->aperture + scr->storage - 96*1024);
-	else
+	switch (scr->id & 0x0ff0) {
+	case 0x0020:
+	case 0x00A0:
 		p = KADDR(scr->io + Pramin + 0x1E00 * 4);
+		break;
+	default:
+		p = KADDR(scr->aperture + scr->storage - 96*1024);
+		break;
+	}
 
 	for(i=0; i<16; i++) {
 		c = (curs->clr[2 * i] << 8) | curs->clr[2 * i+1];