i40e: clean up local variable initialization
i40e: clean up local variable initialization

In both i40e_calc_nvm_checksum() and i40e_update_nvm_checksum(), the
local variables designated by 'ret_code' are overwritten immediately. As
such, they should merely be declared.

Signed-off-by: Jean Sacren <c8d76beebf61dec12040ee2ca9c37594ab0bec6b@gmail.com>
Tested-by: Andrew Bowers <bda1442b63f5d3779efd9a7804382f1971792f1d@intel.com>
Signed-off-by: Jeff Kirsher <87e35f5be20bb3e67f4ba6b86f5f6be3085b1b3a@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs