Current Koelsch I2C2 has 400kHz settings,
but, ak4643 audio codec chip which is connected to I2C2 can't
work such frequency.
Fixup I2C2 clock frequency to 100kHz.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>