Due to what seems to be an undocumented oddity in MediaTek's MT7988
SoC design the CLK_INFRA_PCIE_PERI_26M_CK_P2 clock requires
CLK_INFRA_PCIE_PERI_26M_CK_P3 to be enabled.
This currently leads to PCIe port 2 not working in Linux.
Reflect the apparent relationship in the clk driver to make sure PCIe
port 2 of the MT7988 SoC works.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>