intel/gma: consolidate vbt code

Change-Id: I80b7facfb9cc9f642dd1c766884dc23da1aab2c8
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/6800
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/include/smbios.h

@@ -19,6 +19,7 @@ const char *smbios_mainboard_serial_number(void);
 const char *smbios_mainboard_version(void);
 void smbios_mainboard_set_uuid(u8 *uuid);
 const char *smbios_mainboard_bios_version(void);
+u8 smbios_mainboard_enclosure_type(void);
 
 #define BIOS_CHARACTERISTICS_PCI_SUPPORTED  (1 << 7)
 #define BIOS_CHARACTERISTICS_PC_CARD  (1 << 8)