wifi: carl9170: Remove redundant assignment to pointer super

The pointer super is being assigned a value that is not being read, it
is being re-assigned later. The assignment is redundant and can be
removed.

Cleans up clang scan warning:

drivers/net/wireless/ath/carl9170/tx.c:192:34: warning: Value stored to
'super' during its initialization is never read [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240207171524.2458418-1-colin.i.king@gmail.com