ppc4xx/POST: Add board specific UART POST test to lwmon5

Add CONFIG_POST_UART to implement a board specific UART POST test.
This is done since lwmon5 needs to set POST_ALWAYS to run this
test on each reboot. And we don't want to change the default
behavious of this this.

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