tls_wolfssl: Fix tarball generation

Since ".patch" files are explicitly excluded during tarball packing,
let's just rename the patch file to ".diff" instead so it gets included,
thus allowing the tarball module code to compile once again.

(cherry picked from commit 82876a7)

modules/tls_wolfssl/Makefile

@@ -30,7 +30,7 @@ lib/lib/libwolfssl.a: lib/wolfssl/Makefile $(PATCHED_FILES)
 
 lib/wolfssl/src/internal.c: lib/patches/wolfssl-internal-memleak-fix.patched
 
-lib/patches/wolfssl-internal-memleak-fix.patched: lib/patches/wolfssl-internal-memleak-fix.patch
+lib/patches/wolfssl-internal-memleak-fix.patched: lib/patches/wolfssl-internal-memleak-fix.diff
 	 $(Q)patch -sNR -p1 -d lib/wolfssl --dry-run < $< || patch -N -p1 -d lib/wolfssl  < $< && cp $< $@
 
 clean:	clean-wolfssl-lib
@@ -40,7 +40,7 @@ clean-wolfssl-lib:
 	-@if [ -f ./lib/wolfssl/Makefile ]; then \
 		$(MAKE) -C ./lib/wolfssl clean; \
 	fi;
-	-@patch -stNR -p1 -d lib/wolfssl < lib/patches/wolfssl-internal-memleak-fix.patch
+	-@patch -stNR -p1 -d lib/wolfssl < lib/patches/wolfssl-internal-memleak-fix.diff
 	-@rm -rf ./lib/bin ./lib/include ./lib/lib ./lib/share \
 	./lib/wolfssl/Makefile ./lib/wolfssl/configure \
 	lib/patches/wolfssl-internal-memleak-fix.patched