ARM: shmobile: Remove Lager DT reference legacy clock bits

Lager DT reference is these days built for multiplatform
only which means that CCF comes with the package. Remove
unused legacy code ifdefs to clean up the code.

Signed-off-by: Magnus Damm <damm@opensource.se>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>