xen: remove a confusing comment on auto-translated guest I/O

xen: remove a confusing comment on auto-translated guest I/O

[ Upstream commit d826c9e61c99120f8996f8fed6417167e32eb922 ]

After removing the conditional return from xen_create_contiguous_region(),
the accompanying comment was left in place, but it now precedes an
unrelated conditional and confuses readers.

Fixes: 989513a735f5 ("xen: cleanup pvh leftovers from pv-only sources")
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20230802163151.1486-1-petrtesarik@huaweicloud.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Stable-dep-of: e93ec87286bd ("x86/xen: allow larger contiguous memory regions in PV guests")
Signed-off-by: Sasha Levin <sashal@kernel.org>