ath9k: fix invalid pointer access in the tx path

ath9k: fix invalid pointer access in the tx path

After setup_frame_info has been called, only info->control.rates is still
valid, other control fields have been overwritten by the ath_frame_info
data. Move the access to info->control.vif for checking short preamble
to setup_frame_info before it gets overwritten.

This regression was introduced in commit d47a61aa
"ath9k: Fix multi-VIF BSS handling"

Signed-off-by: Felix Fietkau <[email protected]>
Reported-by: Thomas Hühn <[email protected]>
Acked-by: Sujith Manoharan <[email protected]>
Cc: [email protected] [3.4]
Signed-off-by: John W. Linville <[email protected]>