yam_open has a redundant null check on null, it will
never be called with dev == NULL. Remove this redundant check.
This also cleans up a smatch warning:
drivers/net/hamradio/yam.c:869 yam_open() warn: variable
dereferenced before check 'dev' (see line 867)
Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>