mac80211-hwsim: remove unnecessary hwname check

The hwname will always be set if idx is negative (as it's
a u32 read into an s64 it can't overflow either) so we can
remove the unnecessary check for hwname being non-NULL.

This was reported by smatch.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --cc drivers/net/wireless/mac80211_hwsim.c
Simple merge