ANDROID: GKI: Enable CONFIG_SERIAL_8250_RUNTIME_UARTS=0

8250_core registers 4 ISA uart ports by default, which can cause
problems on some devices which don't have them. This change doesn't
break earlycon=uart8250, but it will cause the 8250_of and 8250_pci sub
drivers to be unable to register ports. Boards that really need the full
8250 driver to take over from earlycon can use the "8250.nr_uarts=X"
kernel command line option to restore the ports allocation.

Bug: 216312411
Signed-off-by: Alistair Delva <adelva@google.com>
Change-Id: I04715394b32bd98544657101de4537df34554ea9