vgabios: Make sure exported structs use PACKED.

Commit ca668640 introduced structs for data returned from the
handle_101b and handle_101c calls.  However, the structs were not
declared as packed and that caused incorrect behavior for
handle_101b.  This was seen to break some old DOS programs (Win3 setup
and DISPLAY.SYS).  This patch adds in the necessary PACKED declaration
to the structs.

The 'struct saveBDAstate' remains un-packed, as it does not appear
that its contents are documented.  (And, its format already differs
from what was in the previous "lgpl vgabios".)

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/vgasrc/stdvga.c b/vgasrc/stdvga.c
index e0661f1..c94ec06 100644
--- a/vgasrc/stdvga.c
+++ b/vgasrc/stdvga.c
@@ -338,7 +338,7 @@
     u8 grdc_regs[9];
     u16 crtc_addr;
     u8 plane_latch[4];
-};
+} PACKED;
 
 static void
 stdvga_save_hw_state(u16 seg, struct saveVideoHardware *info)
@@ -412,7 +412,7 @@
     u8 pelmask;
     u8 dac[768];
     u8 color_select;
-};
+} PACKED;
 
 static void
 stdvga_save_dac_state(u16 seg, struct saveDACcolors *info)
diff --git a/vgasrc/vgabios.c b/vgasrc/vgabios.c
index 57f1c1f..f70b2b6 100644
--- a/vgasrc/vgabios.c
+++ b/vgasrc/vgabios.c
@@ -1114,7 +1114,7 @@
     u8 save_flags;
     u8 disp_info;
     u8 reserved_34[12];
-};
+} PACKED;
 
 static void
 handle_101b(struct bregs *regs)