ATI Mach32/64 changes for the better:

1. On both Mach'es: direct linear video memory access is now the default for LFB mapping: fixes Mach64 drivers on NeXTSTEP/OPENSTEP and keeps everything else intact.
2. Mach8/32: minor cleanup to mode change code.

src/include/86box/vid_8514a.h

@@ -32,6 +32,13 @@ typedef struct hwcursor8514_t {
     uint32_t pitch;
 } hwcursor8514_t;
 
+typedef union {
+    uint64_t q;
+    uint32_t d[2];
+    uint16_t w[4];
+    uint8_t  b[8];
+} latch8514_t;
+
 typedef struct ibm8514_t {
     rom_t bios_rom;
     rom_t bios_rom2;
@@ -217,6 +224,8 @@ typedef struct ibm8514_t {
     int      ext_pitch;
     int      ext_crt_pitch;
     int      extensions;
+
+    latch8514_t latch;
 } ibm8514_t;
 
 #endif /*VIDEO_8514A_H*/