iwlwifi: pcie: update bytes in the byte count table

For devices which use the image loader image, the length of the frame
must be updated in the byte count in bytes, and not dwords as today.
Avoid dividing the input length by 4.

Signed-off-by: Golan Ben Ami <golan.ben.ami@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>