Use the clock framework to get the rate of the peripheral clock.
Remove the now obsolete get_uart_baud_base function.
Signed-off-by: NManuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/7468/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>