i965: allow SIMD8 sampler messages in SIMD16 mode

When the instruction to send the sampler message is forced uncompressed or
sechalf, send SIMD8 one even in SIMD16 mode.

Signed-off-by: Chia-I Wu <olv@lunarg.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
diff --git a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
index 4159773..dbfbc11 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
@@ -381,7 +381,8 @@
       break;
    }
 
-   if (dispatch_width == 16)
+   if (dispatch_width == 16 &&
+      !inst->force_uncompressed && !inst->force_sechalf)
       simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
 
    if (brw->gen >= 5) {