Kconfig: Fix CONFIG_GDB_STUB dependencies

If we select CONFIG_GDB_STUB without CONFIG_SERIAL:

build/console/console.romstage.o: In function `__gdb_hw_init':
[...]src/include/console/uart.h:74: undefined reference to `uart_init'
build/console/console.romstage.o: In function `__gdb_tx_byte':
[...]/src/include/console/uart.h:75: undefined reference to `uart_tx_byte'
build/console/console.romstage.o: In function `__gdb_tx_flush':
[...]/src/include/console/uart.h:76: undefined reference to `uart_tx_flush'
build/console/console.romstage.o: In function `__gdb_rx_byte':
[...]/src/include/console/uart.h:77: undefined reference to `uart_rx_byte'

Note that CONFIG_GDB_STUB should also work trough usbdebug,
But due to the lack of testing, it has been disabled when added.
This commit gives more information on the issue:
f2f7f03 console: Add console for GDB

Change-Id: I9accf8189dfd2c4ae379c03649d2e5863183457b
Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@no-log.org>
Reviewed-on: https://review.coreboot.org/12708
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
1 file changed