aufs: linux-v5.10-rc1, no more set_fs()

Finally set_fs() is gone by the commit,
	3c57fa13 2020-10-04 asm-generic: make the set_fs implementation optional
Now aufs removes all [gs]et_fs() calls.  It heavily affects XINO file
I/O and some others.

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
(cherry picked from commit 70f8bb837bce181cc2e11d60005b548013e96aa0
 in https://github.com/sfjro/aufs5-linux

)
Signed-off-by: Vefa Bicakci <vefa.bicakci@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>