bdinfo: ppc: Drop arch-specific print_baudrate()

This function outputs the same basic info. Since the baud rate is commonly
115200 these is often no difference. Drop the arch-specific code and
inline it to avoid a one-line function.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>