ARM: shmobile: bockw: remove old style audio clock

Current audio clock didn't have dependency to device/driver,
but, it was not good design for DT support.
To avoid branch merge conflict issue,
it is using this load map, and this patch is 3) part.
 1) add new style clock in platform
 2) add new style clock method in driver
 3) remove old tyle clock from platform

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>