arm64: defconfig: Enable PCIe on msm8996 and db820c

The msm8996 PCIe sits behind the "agnoc0", which is represented as a
simple-pm-bus, so enable support for this. Then enable the QMP phy
driver.

Also enable the atl1c ethernet driver and ath10k wlan driver to support
these components on the DragonBoard820c.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>