i2c: sh_mobile: fix clock calculation for newer SoCs

i2c: sh_mobile: fix clock calculation for newer SoCs

Newer SoCs have so fast input clocks that the ICCL/H registers only
count every second clock to have a meaningful 9-bit range. The driver
was already prepared for that happening, but didn't use it so far.
Add the proper DT configuration for SoCs that need it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
(cherry picked from commit 67240dfcb8dcf756cc00fb37f5cb7e3ee2fa6190)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>