Some newer cards supported by aacraid can take up to 40s to recover
after an EEH event. This causes spurious failures in the basic EEH
self-test since the current maximim timeout is only 30s.

Fix the immediate issue by bumping the timeout to a default of 60s,
and allow the wait time to be specified via an environmental variable
(EEH_MAX_WAIT).
Reported-by: Steve Best <sbest@redhat.com>
Suggested-by: Douglas Miller <dougmill@us.ibm.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200122031125.25991-1-oohall@gmail.com