Revert "parisc: Use ldcw instruction for SMP spinlock release barrier"

This reverts commit 9e5c602186a692a7e848c0da17aed40f49d30519.
No need to use the ldcw instruction as SMP spinlock release barrier.
Revert it to gain back speed again.

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