Revert "85xx: Using proper I2C source clock divider for MPC8544"

This reverts commit dffd2446.

The fix introduced by this patch is not correct.  The problem is
that the documentation is not correct for the MPC8544 with regards
to which bit in PORDEVSR2 is for the SEC_CFG.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>