prepare 16550 UART driver to support PCI:
- [breaking change] change argument of uart_ioctl() from `struct file *filep` to `FAR struct u16550_s *priv`
Also fix moxart_16550.c build related to this change
- [breaking change] change argument of uart_getreg() and uart_putreg from `uart_addrwidth_t base` to `FAR struct u16550_s *priv`
Also fix arch/x86/src/qemu/qemu_serial.c and arch/x86_64/src/intel64/intel64_serial.c related to this change
- [breaking change] change argument of uart_dmachan() from `uart_addrwidth_t base` to `FAR struct u16550_s *priv`
- move `struct u16550_s` to public header
- generalize UART_XXX_OFFSET so we can use it with any register increment
- make u16550_bind(), u16550_interrupt(), u16550_interrupt() public
- remove arch/or1k/src/common/or1k_uart.c and use common 16550 MIMO interfacve
- change irq type in `struct u16550_s` from uint8_t to int to match MSI API
Signed-off-by: p-szafonimateusz <p-szafonimateusz@xiaomi.com>