MAINTAINERS: Remove deleted file from futex file pattern

kernel/futex_compat.c was recently removed, but it's still in the
MAINTAINERS file. Remove it there as well.

Fixes: 04e7712f ("y2038: futex: Move compat implementation into futex.c")
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>

MAINTAINERS

@@ -6408,7 +6408,6 @@ L:	linux-kernel@vger.kernel.org
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking/core
 S:	Maintained
 F:	kernel/futex.c
-F:	kernel/futex_compat.c
 F:	include/asm-generic/futex.h
 F:	include/linux/futex.h
 F:	include/uapi/linux/futex.h