Revert "SUNRPC: Declare RPC timers as TIMER_DEFERRABLE"

Jon Hunter reports:
  "I have been noticing intermittent failures with a system suspend test on
   some of our machines that have a NFS mounted root file-system. Bisecting
   this issue points to your commit 43123581 ("SUNRPC: Declare RPC
   timers as TIMER_DEFERRABLE") and reverting this on top of v5.2-rc3 does
   appear to resolve the problem.

   The cause of the suspend failure appears to be a long delay observed
   sometimes when resuming from suspend, and this is causing our test to
   timeout."

This reverts commit 43123581.

Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>