The only things prevent drivers/serial/pxa.c from being generic enough
are:
1. IER_UUE which can be safely replaced by UART_IER_UUE as defined in
serial_reg.h for PXA
2. __PREG() and FFUART/BTUART/STUART definitions to decide the UART
port name
And removed the un-necessary #include of <mach/...> and <asm/...> headers.
Signed-off-by: Eric Miao <eric.miao@marvell.com>