net: socket: Use exponential backoff in case of polling errors

Some errors can occur in the sending process that have to be handled
in a polling fasion instead of blocking using semaphores. In this case
apply an exponentially growing backoff time. This will allow for fast
reactions in most situations and prevents high system loads in case
resolving the situation takes a little longer.

Signed-off-by: Sjors Hettinga <s.a.hettinga@gmail.com>