ath10k: fix possible wrong rx_busy time reporting in QCA4019

As hw cycle counters in QCA4019 wraparound independantly in QCA4019
it is possible cycle counter and rx clear counter would wraparound
at the same time. Current logic assumes only one of the counters
would wraparound at anytime. Fix this by moving 'else' part to
another 'if'.

Fixes: 8e100354 ("ath10k: fix cycle counter wraparound handling for QCA4019")
Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qti.qualcomm.com>
Reviewed-by: Julian Calaby <julian.calaby@gmail.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>