debian/control: Remove "Maintainer" from binary package section

This resolves the following warning:
dpkg-source: warning: unknown information field 'Maintainer' in input data in package's section of control info file

Change-Id: I7a8d8c54eabccc5cedf7ad0a2bccf91f32f1bfdf
diff --git a/debian/control b/debian/control
index 73e2a7a..4705e64 100644
--- a/debian/control
+++ b/debian/control
@@ -19,7 +19,6 @@
 Homepage: https://projects.osmocom.org/projects/osmotrx
 
 Package: osmo-trx
-Maintainer: Ivan Klyuchnikov <ivan.kluchnikov@fairwaves.ru>
 Depends: osmo-trx-uhd
 Architecture: all
 Description: Metapackage for osmo-trx-uhd