wg: remove unused check phony declaration

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
diff --git a/src/Makefile b/src/Makefile
index 483b703..f2904f2 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -89,6 +89,6 @@
 help:
 	@cat INSTALL
 
-.PHONY: clean install check help
+.PHONY: clean install help
 
 -include *.d