i965/fs: Fix an uninitialized value warnings

Signed-off-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 19e9cb9..fd59ef8 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2975,10 +2975,11 @@
 
    foreach_block_and_inst_safe (block, fs_inst, inst, cfg) {
       int dst_reg;
-      if (inst->dst.file == MRF) {
-         dst_reg = inst->dst.reg;
-      } else if (inst->dst.file == GRF) {
+      } if (inst->dst.file == GRF) {
          dst_reg = vgrf_to_reg[inst->dst.reg];
+      } else {
+         /* MRF */
+         dst_reg = inst->dst.reg;
       }
 
       if (inst->dst.file == MRF || inst->dst.file == GRF) {