system/uart: refactor debug_uart, fix arm uart

* Drop ArchUART8260 layer to reduce complexity. It's whole
existance in life was to adjust the mmio alignment.
* Fold architecture mmio alignment into DebugUart
* We could potentially pass a Init(int mmioAlignment)
arg in the future if the macros get too messy.
* Move Barrier code back a layer into DebugUART
* Fixes the arm uart and EFI build

Change-Id: I0f127d902993e9f6e6a03cac8c7c37c0363134bf
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4422
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>

kernel/uart: Fix PPC, drop needless abstraction

Change-Id: I4b8f69271ede117701725f9cce30de5bb8ba30bb
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4332
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>
Reviewed-by: Jessica Hamilton <jessica.l.hamilton@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>

Style fixes to various parts of the system.

Signed-off-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

This patch was never applied after GSoC 2012. Rebase the parts that
still apply so we can close the ticket.

Fixes #9490.

Attempt to factor out serial stuff

* introduce a DebugUART baseclass,
* rework 8250 and PL011 implementations from kallisti5 to inherit DebutUART,
* each arch should override the IO methods to access registers.
* on ARM registers are 32bit-aligned.
* U-Boot still works for the verdex target.
* rPi still compiles, needs testing.
* Still some more consolidation needed to allow runtime choice of the UART type (as read from FDT blobs for ex.).
* serial.cpp should probably mostly be made generic as well.
* didn't touch x86 or ppc yet.

Attempt to factor out serial stuff

* introduce a DebugUART baseclass,
* rework 8250 and PL011 implementations from kallisti5 to inherit DebutUART,
* each arch should override the IO methods to access registers.
* on ARM registers are 32bit-aligned.
* U-Boot still works for the verdex target.
* rPi still compiles, needs testing.
* Still some more consolidation needed to allow runtime choice of the UART type (as read from FDT blobs for ex.).
* serial.cpp should probably mostly be made generic as well.
* didn't touch x86 or ppc yet.