freedreno: Add .dir-locals to the common directory

The commit aa0fed10d3 moved a bunch of Freedreno code to a common
directory. The previous directory had a .dir-locals file for Emacs.
This patch copies it to the new directory as well.

Reviewed-by: Kristian H. Kristensen <hoegsberg@chromium.org>

src/freedreno/.dir-locals.el

@@ -0,0 +1,8 @@
+((prog-mode
+  (indent-tabs-mode . t)
+  (tab-width . 4)
+  (c-basic-offset . 4)
+  (c-file-style . "k&r")
+  (fill-column . 78)
+  )
+ )