[L3GD20] Add fifo entrypoint

sbs.conf

@@ -475,6 +475,14 @@ Include:    %shared %spi
 Defines:
 Main:       drivers/test-l3gd20
 
+[test-l3gd20-fifo]
+Type:       test
+BoardId:    stm32f429zi_stm32f4discovery
+BinName:    test-l3gd20-fifo
+Include:    %shared %spi
+Defines:
+Main:       drivers/test-l3gd20-fifo
+
 [test-rls]
 Type:       test
 BoardId:    stm32f429zi_skyward_death_stack