PCI: j721e: Fix the value of .linkdown_irq_regfield for J784S4

PCI: j721e: Fix the value of .linkdown_irq_regfield for J784S4

Commit e49ad667815d ("PCI: j721e: Add TI J784S4 PCIe configuration")
assigned the value of .linkdown_irq_regfield for the J784S4 SoC as the
"LINK_DOWN" macro corresponding to BIT(1), and as a result, the Link
Down interrupts on J784S4 SoC are missed.

According to the Technical Reference Manual and Register Documentation
for the J784S4 SoC[1], BIT(1) corresponds to "ENABLE_SYS_EN_PCIE_DPA_1",
which is not the correct field for the link-state interrupt. Instead, it
is BIT(10) of the "PCIE_INTD_ENABLE_REG_SYS_2" register that corresponds
to the link-state field named as "ENABLE_SYS_EN_PCIE_LINK_STATE".

Thus, set .linkdown_irq_regfield to the macro "J7200_LINK_DOWN", which
expands to BIT(10) and was first defined for the J7200 SoC. Other SoCs
already reuse this macro since it accurately represents the "link-state"
field in their respective "PCIE_INTD_ENABLE_REG_SYS_2" register.

1: https://www.ti.com/lit/zip/spruj52

Fixes: e49ad667815d ("PCI: j721e: Add TI J784S4 PCIe configuration")
Cc: stable@vger.kernel.org
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
[kwilczynski: commit log, add a missing .linkdown_irq_regfield member
set to the J7200_LINK_DOWN macro to struct j7200_pcie_ep_data]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Link: https://lore.kernel.org/r/20250305132018.2260771-1-s-vadapalli@ti.com