ppc4xx: Fix incorrect 33/66MHz PCI clock log-message on Sequoia & Yosemite

The BCSR status bit for the 66MHz PCI operation was correctly
addressed (MSB/LSB problem). Now the correct currently setup
PCI frequency is displayed upon bootup.

This patch also fixes this problem on Rainier & Yellowstone, since these
boards use the same souce code as Sequoia & Yosemite do.

Signed-off-by: Stefan Roese <sr@denx.de>