serial/mpc52xx_uart: Drop outdated comments

Most things mentioned are either obsolete (platform-support) or wrong (device
numbering, DCD spport) these days. The remaining rest is obvious.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
1 file changed