meson: build r600 driver

v4: - Ensure inc_amd_common defined when radeonsi is disabled (needed by
      r600)

Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>
Tested-by: Aaron Watry <awatry@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
6 files changed