ath11k: refine the phy_id check in ath11k_reg_chan_list_event

For QCA6390, it processes the reg chan list event only for phy0,
and it goes to fallback if the phy_id is not valid. For a valid
phy_id but not 0, just discard the event.

Tested-on: QCA6390 hw2.0 PCI WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1
Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.1.0.1-01238-QCAHKSWPL_SILICONZ-2

Signed-off-by: Carl Huang <cjhuang@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1597555891-26112-5-git-send-email-kvalo@codeaurora.org