sparc64: fix vio handshake issue

sparc64: fix vio handshake issue

When rebooting multiple LDoms together with bind/unbind a separate
LDom, kernel panic with vio handshake error. The panic is caused by
vio trying to allocate a buffer which is not freed properly. The
ldc_unbind should unconfigure and stop the ldc queue before freeing
the irq. If the irq is freed before stopping the queue, interrupts
can continue to happen after the irq is freed which may cause
issue.

Orabug: 26259622

Signed-off-by: Thomas Tai <thomas.tai@oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com>