This controller supports UltraDMA up to mode 5 but it should be clocked with
at least twice the data strobe frequency, so enable mode 5 for 100+ MHz IDECLK.

While at it, start passing the correct device to clk_get() -- it worked anyway
but WTF? :-/
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>