serial: core: Move struct uart_port::quirks closer to possible values

Currently it's not crystal clear what UPIO_* and UPQ_* definitions
belong to. Reindent the code, so it will be easy to read and understand.
No functional changes intended.

Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240304123035.758700-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>