ath9k: better position PAPRD debug message

the training power calculation indirectly depends on target power under
some scenarios, unless we have a valid training power, the PAPRD frames
won't be sent out. so when we get an invalid training power, its better
to display them before returning back.

Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>