gallium: add separate PIPE_CAP_INT64_DIVMOD

Nouveau does not currently have logic to implement this as a library
function. Even though such a library could be written, there's no big
advantage to do it that way for now given that int64 is a very uncommon
use-case. Allow a driver to expose INT64 without supporting division and
modulo operations.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
diff --git a/src/gallium/drivers/llvmpipe/lp_screen.c b/src/gallium/drivers/llvmpipe/lp_screen.c
index 0b12119..76a30a6 100644
--- a/src/gallium/drivers/llvmpipe/lp_screen.c
+++ b/src/gallium/drivers/llvmpipe/lp_screen.c
@@ -269,6 +269,7 @@
    case PIPE_CAP_TGSI_ARRAY_COMPONENTS:
    case PIPE_CAP_DOUBLES:
    case PIPE_CAP_INT64:
+   case PIPE_CAP_INT64_DIVMOD:
       return 1;
 
    case PIPE_CAP_VENDOR_ID: