ARM: shmobile: r7s72100: really add i2c clocks

Due to a merge conflict, addition of the clocks was lost. Tested with
RIIC2 on a genmai board. Others untested but hopefully trivial enough to
be added.

Signed-off-by: Wolfram Sang <wsa@sang-engineering.com>
[horms+renesas@verge.net.au: Capitalised "ARM" in subject]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>