e1000: FIX: move length adjustment due to crc stripping disabled.

Move the length (rx_bytes counter) adjustment of 4 bytes down to after the
TBI_ACCEPT workaround.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>