drm/grate: fixup include path
I was facing a build error when building out of tree:
# CC drivers/gpu/drm/grate/drm.o arm-linux-gnueabihf-gcc ... -I /home/user/p4wifi/linux-v6.12.5-lts//home/user/p4wifi/linux-v6.12.5-lts/drivers/gpu/drm/grate -I /home/user/p4wifi/linux-v6.12.5-lts//home/user/p4wifi/linux-v6.12.5-lts/drivers/gpu/drm/grate/uapi ... -c -o drivers/gpu/drm/grate/drm.o /home/roman/rstanchak/p4wifi/linux-v6.12.5-lts/drivers/gpu/drm/grate/drm.c /home/roman/rstanchak/p4wifi/linux-v6.12.5-lts/drivers/gpu/drm/grate/drm.c:26:10: fatal error: uapi.h: No such file or directory 26 | #include "uapi.h"
This patch uses the $(src)
variable to refer to the current source directory in a consistent manner with other drivers to add an internal include path.