buildman: Add gcc-11.1.0 to the directory list

While CI has been using gcc-11.1.0 for a long time, we have not updated
buildman to match.  Correct this omission.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/tools/buildman/toolchain.py b/tools/buildman/toolchain.py
index fd137f7..4e2471f 100644
--- a/tools/buildman/toolchain.py
+++ b/tools/buildman/toolchain.py
@@ -498,7 +498,7 @@
         if arch == 'aarch64':
             arch = 'arm64'
         base = 'https://www.kernel.org/pub/tools/crosstool/files/bin'
-        versions = ['9.2.0', '7.3.0', '6.4.0', '4.9.4']
+        versions = ['11.1.0', '9.2.0', '7.3.0', '6.4.0', '4.9.4']
         links = []
         for version in versions:
             url = '%s/%s/%s/' % (base, arch, version)