i965/fs: Drop unnecessary write-enable-all from SET_SAMPLE_ID.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>
diff --git a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
index 20461e8..cee7c68 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
@@ -1504,18 +1504,18 @@
    assert(src0.type == BRW_REGISTER_TYPE_D ||
           src0.type == BRW_REGISTER_TYPE_UD);
 
-   brw_push_insn_state(p);
-   brw_set_default_exec_size(p, BRW_EXECUTE_8);
-   brw_set_default_compression_control(p, BRW_COMPRESSION_NONE);
-   brw_set_default_mask_control(p, BRW_MASK_DISABLE);
    struct brw_reg reg = stride(src1, 1, 4, 0);
    if (dispatch_width == 8) {
       brw_ADD(p, dst, src0, reg);
    } else if (dispatch_width == 16) {
+      brw_push_insn_state(p);
+      brw_set_default_exec_size(p, BRW_EXECUTE_8);
+      brw_set_default_compression_control(p, BRW_COMPRESSION_NONE);
       brw_ADD(p, firsthalf(dst), firsthalf(src0), reg);
+      brw_set_default_compression_control(p, BRW_COMPRESSION_2NDHALF);
       brw_ADD(p, sechalf(dst), sechalf(src0), suboffset(reg, 2));
+      brw_pop_insn_state(p);
    }
-   brw_pop_insn_state(p);
 }
 
 void