clk: mpc85xx: Update the compatible string

The compatible string of clock is changed from *-2 to *-2.0
on chassis 2. So updated it accordingly.

Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: improved $SUBJECT line]