x86/build/defconfig: Enable USB_EHCI_TT_NEWSCHED=y

Some Gentoo users are encountering problems because
USB_EHCI_TT_NEWSCHED isn't set in the defconfig (and Gentoo
differs from other distros in not providing a distro .config).
Alan Stern has said there's no reason to not set it, and the
ability to turn it off at all should probably be yanked:

  http://article.gmane.org/gmane.linux.usb.general/119920

This addresses issue:

  https://bugs.gentoo.org/show_bug.cgi?id=533472



(The problem also theoretically affects the sh, arm, mips,
powerpc, and sparc archs, but those would be other patches if
this one that fixes 98% of the problem is accepted).

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>