PCI: imx6: Fix device node reference leak in imx_pcie_probe()

PCI: imx6: Fix device node reference leak in imx_pcie_probe()

In imx_pcie_probe(), of_parse_phandle() returns the device node pointer
with increased refcount. The pointer reference must be dropped by the
caller when it's no longer needed. However, imx_pcie_probe() doesn't drop
the reference, causing reference leak.

Fix this by using the __free(device_node) cleanup handler to drop the
reference when the function goes out of scope.

Fixes: 1df82ec46600 ("PCI: imx: Add workaround for e10728, IMX7d PCIe PLL failure")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
[mani: commit log]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
Link: https://patch.msgid.link/20260124-pci_imx6-v2-1-acb8d5187683@gmail.com