serial: sc16is7xx: fix invalid sc16is7xx_lines bitfield in case of probe error

serial: sc16is7xx: fix invalid sc16is7xx_lines bitfield in case of probe error

commit 8a1060ce974919f2a79807527ad82ac39336eda2 upstream.

If an error occurs during probing, the sc16is7xx_lines bitfield may be left
in a state that doesn't represent the correct state of lines allocation.

For example, in a system with two SC16 devices, if an error occurs only
during probing of channel (port) B of the second device, sc16is7xx_lines
final state will be 00001011b instead of the expected 00000011b.

This is caused in part because of the "i--" in the for/loop located in
the out_ports: error path.

Fix this by checking the return value of uart_add_one_port() and set line
allocation bit only if this was successful. This allows the refactor of
the obfuscated for(i--...) loop in the error path, and properly call
uart_remove_one_port() only when needed, and properly unset line allocation
bits.

Also use same mechanism in remove() when calling uart_remove_one_port().

Fixes: c64349722d14 ("sc16is7xx: support multiple devices")
Cc:  <stable@vger.kernel.org>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231221231823.2327894-2-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>