e1000e: cleanup: use goto for common work needed by multiple exit points

There are two exit points of e1000e_write_nvm_spi() which require the
nvm->ops.release() function pointer called just before exiting.
Consolidate the two duplicate pieces of common work with a goto.  With
this change, the value ret_val will need to be returned instead of 0.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>