arm64: dts: qcom: ipq8074: fix Gen2 PCIe QMP PHY

Serdes register space sizes are incorrect, update them to match the
actual sizes from downstream QCA 5.4 kernel.

Fixes: 942bcd33 ("arm64: dts: qcom: Fix IPQ8074 PCIe PHY nodes")
Signed-off-by: Robert Marko <robimarko@gmail.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230113164449.906002-1-robimarko@gmail.com