package/linux-tools: gpio does not build in parallel

Partially fixes #10276.

Reported-by: Ciro Santilli <ciro.santilli@gmail.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Ciro Santilli <ciro.santilli@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>