radeonsi: remove emacs style config file

As radeonsi has synced the code style with main mesa,
remove the orginal radeonsi spec emacs config file and
use the top level dir .dir-locals.el

Acked-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4961>

src/gallium/drivers/radeonsi/.dir-locals.el

@@ -1,11 +0,0 @@
-((prog-mode
-  (indent-tabs-mode . t)
-  (tab-width . 8)
-  (c-basic-offset . 8)
-  (c-file-style . "stroustrup")
-  (fill-column . 78)
-  (eval . (progn
-	    (c-set-offset 'innamespace '0)
-	    (c-set-offset 'inline-open '0)))
-  )
- )