bitbake: bitbake: cooker: skip when BBFILE_PATTERN is empty

There is nothing to do when BBFILE_PATTERN is empty.

(Bitbake rev: b7da31641c24c53d47ea45a7119d1bd353011b39)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/cooker.py

@@ -1170,6 +1170,7 @@ class BBCooker:
                 elif regex == "":
                     parselog.debug(1, "BBFILE_PATTERN_%s is empty" % c)
                     errors = False
+                    continue
                 else:
                     try:
                         cre = re.compile(regex)