MIPS: Alchemy: Fix db1200 PSC clock enablement

Enable PSC0 (I2C/SPI) clock and leave PSC1 (Audio) alone.  This patch
restores functionality to both Audio and I2C/SPI.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/7544/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>