x11-drivers/xf86-video-ast: restore functionality on 12

AST video which works on 11-, doesn't on 12-, restored by
pulling in some Linux DRM patches and then massaging it to
avoid device-tree madness, from darius@dons.net.au

PR:		240294
Approved by:	zeising (x11@)

x11-drivers/xf86-video-ast/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	xf86-video-ast
 PORTVERSION=	1.1.5
-PORTREVISION=	3
+PORTREVISION=	4
 CATEGORIES=	x11-drivers
 
 MAINTAINER=	x11@FreeBSD.org

x11-drivers/xf86-video-ast/files/patch-ast_vgatool.c

@@ -0,0 +1,33 @@
+--- src/ast_vgatool.c.orig	2015-08-19 01:24:48.000000000 +0000
++++ src/ast_vgatool.c		2020-09-17 14:19:18.843298000 +0000
+@@ -432,11 +432,27 @@
+     *(ULONG *) (pAST->MMIOVirtualAddr + 0xF004) = 0x1e6e0000;
+     *(ULONG *) (pAST->MMIOVirtualAddr + 0xF000) = 0x1;
+
++    /* Based on the Linux DRM driver we might not be able to access this
++     * If we can't just use some sane defaults.
++     *
++     * See drm/drivers/gpu/drm/ast/ast_main.c line 295.
++     */
++
+     *(ULONG *) (pAST->MMIOVirtualAddr + 0x10000) = 0xFC600309;
+-    do {
+-       ;
+-    } while (*(volatile ULONG *) (pAST->MMIOVirtualAddr + 0x10000) != 0x01);
++    for (ulData = 10000; ulData > 0; ulData--)
++	if (*(volatile ULONG *) (pAST->MMIOVirtualAddr + 0x10000) == 0x01)
++	    break;
+
++    if (ulData == 0) {
++	xf86DrvMsg(pScrn->scrnIndex, X_INFO, "Unable to read DRAM information, using defaults\n");
++	pAST->ulDRAMBusWidth = 16;
++	pAST->jDRAMType = DRAMTYPE_1Gx16;
++	if (pAST->jChipType == AST2500)
++	    pAST->ulMCLK = 800;
++	else
++	    pAST->ulMCLK = 396;
++	return;
++    }
+     ulData = *(volatile ULONG *) (pAST->MMIOVirtualAddr + 0x10004);
+
+     /* Get BusWidth */