arm64: dts: qcom: ipq8074: fix PCIe PHY serdes size

The size of the PCIe PHY serdes register region is 0x1c4 and the
corresponding 'reg' property should specifically not include the
adjacent regions that are defined in the child node (e.g. tx and rx).

Fixes: 33057e16 ("ARM: dts: ipq8074: Add pcie nodes")
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220915143431.19842-1-johan+linaro@kernel.org