[settings] Expose SMBIOS settings as global variables

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/settings.h

 busid_setting __setting ( SETTING_NETDEV, busid );
 extern const struct setting
 user_class_setting __setting ( SETTING_HOST_EXTRA, user-class );
+extern const struct setting
+manufacturer_setting __setting ( SETTING_HOST_EXTRA, manufacturer );
+extern const struct setting
+product_setting __setting ( SETTING_HOST_EXTRA, product );
+extern const struct setting
+serial_setting __setting ( SETTING_HOST_EXTRA, serial );
+extern const struct setting
+asset_setting __setting ( SETTING_HOST_EXTRA, asset );
+extern const struct setting
+board_serial_setting __setting ( SETTING_HOST_EXTRA, board-serial );
 
 /**
  * Initialise a settings block

src/interface/smbios/smbios_settings.c

 
 /** Board serial number setting (may differ from chassis serial number) */
 const struct setting board_serial_setting __setting ( SETTING_HOST_EXTRA,
-						      board_serial ) = {
+						      board-serial ) = {
 	.name = "board-serial",
 	.description = "Base board serial",
 	.tag = SMBIOS_STRING_TAG ( SMBIOS_TYPE_BASE_BOARD_INFORMATION,