ath10k: consolidate if statements in ath10k_wmi_event_mgmt_rx

This patch replaces multiple if conditional checks with a single if condition
in WMI management rx handler. Found during code review.

Signed-off-by: Manikanta Pubbisetty <manikanta.pubbisetty@gmail.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>