Add missing files to pkg-plist
This fixes buildkernel when the SOURCE option is turned on:
===> drm-current-kmod (all) --- all_subdir_drm-current-kmod/linuxkpi --- ===> drm-current-kmod/linuxkpi (all) make[4]: make[4]: don't know how to make dma-resv.c. Stop
Approved by: manu