Add empty line in vnd_sawshark.txt to fix build error

The gen-buildcfg.sh would generate vnd_buildcfg.h from vnd_sawshark.txt.
If no empty line in vnd_sawshark.txt, the "#endif" would be added follow
by a "#define" sentence, will lead to make error: unterminated conditional
directive.

Change-Id: I9e9b2047a159836a26d936ab74d6b7c50deeb1f7
diff --git a/include/vnd_sawshark.txt b/include/vnd_sawshark.txt
index 5713959..1f3b0ee 100644
--- a/include/vnd_sawshark.txt
+++ b/include/vnd_sawshark.txt
@@ -12,4 +12,4 @@
 BTVND_DBG = FALSE
 BTHW_DBG = FALSE
 VNDUSERIAL_DBG = FALSE
-UPIO_DBG = FALSE
\ No newline at end of file
+UPIO_DBG = FALSE