ath11k: Rename ath11k_ahb_ext_irq_config

Rename ath11k_ahb_ext_irq_config() to ath11k_ahb_config_ext_irq()
for just symmetry with ath11k_ahb_free_ext_irq().

Signed-off-by: Venkateswara Naralasetty <quic_vnaralas@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/1642583893-21485-1-git-send-email-quic_vnaralas@quicinc.com