vgabios: Extract out common parts of struct vgamode_s.

Extract out the fields in 'struct vgamode_s' that are used in the main
code.  The remaining fields are specific to the standard vga hardware
driver.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/vgasrc/vgahw.h b/vgasrc/vgahw.h
index 23b4f13..55e3bc4 100644
--- a/vgasrc/vgahw.h
+++ b/vgasrc/vgahw.h
@@ -9,6 +9,10 @@
 #include "stdvga.h" // stdvga_set_mode
 #include "geodevga.h" // geodevga_init
 
+static inline struct vgamode_s *vgahw_find_mode(int mode) {
+    return stdvga_find_mode(mode);
+}
+
 static inline int vgahw_set_mode(int mode, int flags) {
     if (CONFIG_VGA_CIRRUS)
         return clext_set_mode(mode, flags);