Revert "parisc: Drop LDCW barrier in CAS code when running UP"

This reverts commit e6eb5fe9123f05dcbf339ae5c0b6d32fcc0685d5.
We need to optimize it differently. A follow up patch will correct it.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.2+
1 file changed