i40e: rework shadow ram read functions

Rework Shadow RAM read word/buffer functions to not use AQ Request
Resource commands.  Requesting resource is not needed for SR read
operations which are done through SRCTL register.  Access to SR through
register is controlled through DONE bit within SRCTL.  With this change
we do not block whole NVM resource for SR read operations.

Change-Id: I73e96cdea39a45ee7b5bdf038e527308de2d9efe
Signed-off-by: Kamil Krawczyk <kamil.krawczyk@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>