package/weston: fix build with headers < 4.4

package/weston: fix build with headers < 4.4

weston includes input-event-codes.h since version 5.0.91 and
https://github.com/wayland-project/weston/commit/6e229ca26381bc8191fd9af1e439c311da709aff

input-event-codes.h is available only since kernel 4.4 and
https://github.com/torvalds/linux/commit/f902dd893427eade90f7eaf858e5ff8b150a5a12

To fix this build failure, replace include on linux/input-event-codes.h
by linux/input.h

Fixes:
 - http://autobuild.buildroot.org/results/210c2759900f15ea0030d088f6f45cd8bb199b29

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>