dist/tools/cosy: provide patch for PR RIOT-OS#13

The upstream PR RIOT-OS#13 is not yet merged but fixes classification to no
longer classify most of RIOT's object files "unspecified" in the
`.text` view.

dist/tools/cosy/patches/0002-parse_elffile-fix-riot_base.patch

@@ -0,0 +1,26 @@
+From ca34f5c4e808b9b6e61e1ceba5e7065bf71fe37a Mon Sep 17 00:00:00 2001
+From: Jana Eisoldt <jana.eisoldt@st.ovgu.de>
+Date: Mon, 21 Feb 2022 16:52:01 +0100
+Subject: [PATCH] parse_elffile: fix riot_base
+
+---
+ cosy.py | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/cosy.py b/cosy.py
+index b36c28a..2081f64 100755
+--- a/cosy.py
++++ b/cosy.py
+@@ -154,9 +154,9 @@ def parse_elffile(elffile, prefix, appdir, riot_base=None):
+     rbase = ["riotbuild/riotproject"]
+     if riot_base:
+         rbase.append(riot_base.strip("/"))
+-    else:
+-        rbase.append("RIOT")
+-        rbase.append("riotbuild/riotbase")
++
++    rbase.append("RIOT")
++    rbase.append("riotbuild/riotbase")
+     riot_base = "|".join([f'{p}/build|{p}' for p in rbase])
+
+     c = re.compile(r"(?P<addr>[0-9a-f]+) "