radv: fix building error after 0833dd7d

It seams that radv is the only driver using header <libdrm/drm_fourcc.h> all others are using header <drm-uapi/drm_fourcc.h>

Fixes the following building error:

external/mesa/src/amd/vulkan/radv_image.c:28:10: fatal error: 'libdrm/drm_fourcc.h' file not found ^~~~~~~~~~~~~~~~~~~~~ 1 error generated.

Fixes: 0833dd7d ("amd/common: Add support for modifiers.") Signed-off-by: Mauro Rossi issor.oruam@gmail.com