include: up the number of max. input devices to 256.

Extending the decade old f0124ed9, to increase the number of input
devices from 40 to 256. 40 translates at most 9 MD, while 256 will allow
63 MD. It is an arbitrary number, but people are hitting the current
limit under reasonable conditions.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=64793
Signed-off-by: Arthur Williams <taaparthur@gmail.com>
3 jobs for bug64793 in 4 minutes and 51 seconds (queued for 1 second)
Status Job ID Name Coverage
  Docker Image
passed #769596
debian-testing

00:00:33

 
  Build And Test
passed #769597
autotools-build-and-test

00:04:17

passed #769598
meson-build-and-test

00:02:04