Use the blit ring for submitting flips since the render ring doesn't
generate flip complete interrupts.

Fixes bugs:

	https://bugs.freedesktop.org/show_bug.cgi?id=38362
	https://bugs.freedesktop.org/show_bug.cgi?id=38392
	https://bugs.freedesktop.org/show_bug.cgi?id=38393Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NKenneth Graunke <kenneth@whitecape.org>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Tested-by: NJian J Zhao <jian.j.zhao@intel.com>
Signed-off-by: NKeith Packard <keithp@keithp.com>