(console,drivers/uart)/Kconfig: Fix dependencies

The dependencies of CONSOLE_SERIAL and DRIVERS_UART were somehow
backwards. Fix that. Now, CONSOLE_SERIAL depends on DRIVERS_UART,
because it's using its interface. The individual UART drivers
select DRIVERS_UART, because they implement the interface and
depend on the common UART code.

Some guards had to be fixed (using CONSOLE_SERIAL now instead of
DRIVERS_UART). Some other guards that were only about compilation
of units were removed. We want to build test as much as possible,
right?

Change-Id: I0ea73a8909f07202b23c88db93df74cf9dc8abf9
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/29572
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/console/Kconfig

@@ -29,7 +29,7 @@ config SQUELCH_EARLY_SMP
 config CONSOLE_SERIAL
 	bool "Serial port console output"
 	default y
-	depends on DRIVERS_UART_8250IO || DRIVERS_UART_8250MEM || HAVE_UART_SPECIAL
+	depends on DRIVERS_UART
 	help
 	  Send coreboot debug output to a serial port.