Revert "serial: 8250: Make SERIAL_8250_RUNTIME_UARTS work correctly"

This reverts commit cfcec52e.

This regresses a longstanding behaviour on X86 systems, which end up with
PCI serial ports moving between ttyS4 and ttyS0 when you bisect to opposite
sides of this commit, resulting in the need to constantly modify the console
setting in order to bisect across it.

Please revert, we can work on solving this for ARM platforms in a less
disruptive way.

Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Cc: Karthik Manamcheri <karthik.manamcheri@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>