imx8mm-tqma8mqml.dtsi has PCIe support, so it should include
<dt-bindings/phy/phy-imx8-pcie.h>.

Otherwise, there are build errors when this SoM dtsi is included
on customers' carrier boards.

While at it, remove the PCI header from imx8mm-tqma8mqml-mba8mx.dts,
which is now unneeded.

Fixes: 1d842831 ("arm64: dts: tqma8mqml: add PCIe support")
Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>