boards: st: nucleo_c071rb: Add pull-up to user button

The NUCLEO-C071RB user manual UM3353 states that "The PC13 I/O used for
the user button must be set in INPUT, pull‑up". The board does not have
an external pull-up fitted.

Signed-off-by: Ben Marsh <ben.marsh@helvar.com>
1 file changed