crypto: algboss - remove NULL check in cryptomgr_schedule_probe()

The for loop will be executed at least once, so i > 0. If the loop
is interrupted before i is incremented (e.g., when checking len for NULL),
i will not be checked.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>