clocksource: sh_tmu: Add memory base to sh_tmu_channel structure
clocksource: sh_tmu: Add memory base to sh_tmu_channel structure

The channel memory base is channel-specific, add it to the channel
structure in preparation for support of multiple channels per device.

Signed-off-by: Laurent Pinchart <ae960578cc5eca7b9b1dbc37d9caa6cb634f35e0@ideasonboard.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs