DLM: Replace nodeid_to_addr with kernel_getpeername

This patch replaces the call to nodeid_to_addr with a call to
kernel_getpeername. This avoids taking a spinlock because it may
potentially be called from a softirq context.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>