net: ethernet: 8390: axnet_cs: remove unused xfer_count variable

clang with W=1 reports
drivers/net/ethernet/8390/axnet_cs.c:653:9: error: variable
  'xfer_count' set but not used [-Werror,-Wunused-but-set-variable]
    int xfer_count = count;
        ^
This variable is not used so remove it.

Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230327235423.1777590-1-trix@redhat.com


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