vgabios: Simplify save/restore mechanism.

Reorganize the save/restore functions to eliminate some boilerplate
code.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/vgasrc/bochsvga.h b/vgasrc/bochsvga.h
index 78b27c8..ae5f75d 100644
--- a/vgasrc/bochsvga.h
+++ b/vgasrc/bochsvga.h
@@ -50,9 +50,7 @@
 int bochsvga_set_displaystart(struct vgamode_s *vmode_g, int val);
 int bochsvga_get_dacformat(struct vgamode_s *vmode_g);
 int bochsvga_set_dacformat(struct vgamode_s *vmode_g, int val);
-int bochsvga_size_state(int states);
-int bochsvga_save_state(u16 seg, void *data, int states);
-int bochsvga_restore_state(u16 seg, void *data, int states);
+int bochsvga_save_restore(int cmd, u16 seg, void *data);
 int bochsvga_set_mode(struct vgamode_s *vmode_g, int flags);
 int bochsvga_setup(void);