MIPS: Alchemy: db1x00: use clk framework

Make use of the clk framework to set up and enable all PSC clocks.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/7469/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>