wireless: correct sparse warning in generated regdb.c

CHECK   net/wireless/regdb.c
net/wireless/regdb.c:8:34: warning: symbol 'reg_regdb' was not declared.  Should it be static?
net/wireless/regdb.c:11:5: warning: symbol 'reg_regdb_size' was not declared. Should it be static?

Simply include the also generated regdb.h.

Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/wireless/genregdb.awk

@@ -21,6 +21,7 @@ BEGIN {
 	print ""
 	print "#include <linux/nl80211.h>"
 	print "#include <net/cfg80211.h>"
+	print "#include \"regdb.h\""
 	print ""
 	regdb = "const struct ieee80211_regdomain *reg_regdb[] = {\n"
 }