build: remove duplicate MAINTAINER from package-dumpinfo.mk

This is an artifact and is not needed. We have already set the
information 'Maintainer:' in the '.packageinfo-*' files.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

include/package-dumpinfo.mk

@@ -44,7 +44,6 @@ $(if $(KCONFIG),Kernel-Config: $(KCONFIG)
 )$(if $(BUILDONLY),Build-Only: $(BUILDONLY)
 )$(if $(HIDDEN),Hidden: $(HIDDEN)
 )Description: $(if $(Package/$(1)/description),$(Package/$(1)/description),$(TITLE))
-$(MAINTAINER)
 @@
 $(if $(Package/$(1)/config),Config:
 $(Package/$(1)/config)