tsnep: Fix resource_size cocci warning

The following warning is fixed, by removing the unused resource size:

drivers/net/ethernet/engleder/tsnep_main.c:1155:21-24:
WARNING: Suspicious code. resource_size is maybe missing with io

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Link: https://lore.kernel.org/r/20211124205225.13985-1-gerhard@engleder-embedded.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>