serial: ns16550: Move PCI access from ofdata_to_platdata() to probe()

Currently the ofdata_to_platdata() method calls dev_read_addr_pci(),
which potentially accesses the parent PCI bus. If this happens before
the parent PCI bus is probed the resulting address will be wrong.

This behavior was triggered by commit 82de42fa ("dm: core:
Allocate parent data separate from probing parent").

According to a comment in drivers/pci/pci-uclass.c [1] accessing
the PCI parent bus in ofdata_to_platdata() is not allowed, and the
access should be moved to the probe() function.

Move the call to dev_read_addr_pci() and the related handling of the
'addr' value from the ofdata_to_platdata() to its own function,
which is then called from the probe() method.

While moving the code, the comment /* try Processor Local Bus device
first */ was dropped. It was initially added with commit 3db886a5
("serial: ns16550: Support ns16550 compatible pci uart devices") and
later made obsolete with commit 33c215af ("dm: pci: Add a function
to read a PCI BAR").

[1] Comment in drivers/pci/pci-uclass.c:
"A common cause of this problem is that this function is called in the
ofdata_to_platdata() method of @dev. Accessing the PCI bus in that
method is not allowed, since it has not yet been probed. To fix this,
move that access to the probe() method of @dev instead."

Fixes: 82de42fa ("dm: core: Allocate parent data separate from probing parent")
Signed-off-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com> # Tested on Intel Galileo