boards: litex_vexriscv: Enable LiteX GPIO driver

Enable LiteX GPIO driver in litex_vexriscv board.

Signed-off-by: Robert Winkler <rwinkler@internships.antmicro.com>
Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
Signed-off-by: Piotr Zierhoffer <pzierhoffer@antmicro.com>
4 files changed