[CODE_OWNERS] Add myself as code owner for MinGW

llvm-svn: 347847
GitOrigin-RevId: c9a23ccd9b3ec7eef96807e902d01c8ab1291bc4

CODE_OWNERS.TXT

diff --git a/CODE_OWNERS.TXT b/CODE_OWNERS.TXT
index 6a0dd0c..67b91f2 100644
--- a/CODE_OWNERS.TXT
+++ b/CODE_OWNERS.TXT
@@ -222,3 +222,7 @@
 N: Jake Ehrlich
 E: jakehehrlich@google.com
 D: llvm-objcopy (tools/llvm-objcopy)
+
+N: Martin Storsjö
+E: martin@martin.st
+D: MinGW