serial: 8250: sanitize uart_port::serial_{in,out}() types

serial: 8250: sanitize uart_port::serial_{in,out}() types

uart_port::{serial_in,serial_out} (and plat_serial8250_port::* likewise)
historically use:
* 'unsigned int' for 32-bit register values in reads and writes, and
* 'int' for offsets.

Make them sane such that:
* 'u32' is used for register values, and
* 'unsigned int' is used for offsets.

While at it, name hooks' parameters, so it is clear what is what.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250611100319.186924-9-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>