ia64: Mark architecture as orphaned

Tony Luck has maintained arch/ia64 for the past 16 years, but mentioned
that he no longer has working ia64 machines, nor time to look at patches,
so he is stepping down as the maintainer.

Fenghua Yu came in as a temporary co-maintainer when Tony was on
sabbatical in 2009, but has not worked on it after that either.

This leaves the architecture as Orphaned, meaning that patches
will have to get routed through other trees from now on.
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
Link: https://lore.kernel.org/lkml/20210105153603.GA17644@agluck-desk2.amr.corp.intel.com/Signed-off-by: Arnd Bergmann <arnd@arndb.de>

MAINTAINERS

@@ -8435,11 +8435,8 @@ F:	drivers/i3c/
 F:	include/linux/i3c/
 
 IA64 (Itanium) PLATFORM
-M:	Tony Luck <tony.luck@intel.com>
-M:	Fenghua Yu <fenghua.yu@intel.com>
 L:	linux-ia64@vger.kernel.org
-S:	Odd Fixes
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux.git
+S:	Orphan
 F:	Documentation/ia64/
 F:	arch/ia64/