MIPS: ralink: Add missing I2C and I2S clocks.

This patch adds two additional clocks required by the audio interface of
the SoCs.

Signed-off-by: John Crispin <john@phrozen.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14897/


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