ath6kl: Rename USB driver's suspend/resume/reset_resume

Rename USB driver's suspend/resume/reset_resume callbacks
with 'pm' prefix. This is necessary to differentiate it from
cfg80211/hif suspend/resume/reset_resume callbacks.

Cc: Sivanesan Rajapupathi <c_srajap@qualcomm.com>
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>