console: uart_console: introduces CONFIG_UART_CONSOLE

This introduces the config option CONFIG_UART_CONSOLE,
and also CONFIG_CONSOLE. The UART console can finally
be disabled if desired.

The defconfigs are also being updated.

Change-Id: I5ebaf6471986deca105971e67fcddb43374de94a
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
21 files changed