io: Provide _inX() and _outX()

Since commit a7851aa5 ("io: change outX() to have their own IO barrier
overrides") and commit 87fe2d54

 ("io: change inX() to have their own
IO barrier overrides"), the outX and inX functions have memory barriers
which can be overridden.

However, the generic logic_pio lib has continued to use readl/writel et al
for IO port accesses, which has weaker barriers on arm64.

Provide generic _inX() and _outX(), which can be used by logic pio.

For consistency, we check for !defined({in,out}X) && !defined(_{in,out}X),
for defining _{in,out}X, while a check for just !defined({in,out}X) should
suffice.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>