kernel/arch/arm: enable 8250 generic and OMAP UART drivers

Change-Id: I45396eada2e9088b27df7fb9522d07e8ac223fd5
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4741
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

arch_uart_8250_omap: fix includes

Change-Id: Ib86d86b4497a46902c3f8d3dd77241f55504d702
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4620
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>
Reviewed-by: Fredrik Holmqvist <fredrik.holmqvist@gmail.com>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

kernel/uart: Clean up uarts, make calling convention consistent

Change-Id: I36ef92ef13edb0b006344db74e9d1b3ae52e0127
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4327
Reviewed-by: X512 <danger_mail@list.ru>
Reviewed-by: Jessica Hamilton <jessica.l.hamilton@gmail.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>