Reformat all gn files in /build/config/linux.

`gn format` recently changed its formatting behavior
for deps, source, and a few other elements when they
are assigned (with =) single-element lists to be consistent
with the formatting of updates (with +=) with single-element.

Now that we've rolled in a GN binary with the change,
reformat all files so that people don't get presubmit
warnings due to this.

This CL was uploaded by git cl split.

R=thomasanderson@chromium.org

Bug: 1041419
Change-Id: I508a1fc4a66d5650bd7f635b45af94827577d2ba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1998623
Auto-Submit: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732533}

build/config/linux/libdrm/BUILD.gn

@@ -23,9 +23,7 @@ if (use_system_libdrm) {
   }
 } else {
   group("libdrm") {
-    public_deps = [
-      "//third_party/libdrm",
-    ]
+    public_deps = [ "//third_party/libdrm" ]
   }
   config("libdrm_exynos_include_config") {
     include_dirs = [ "//third_party/libdrm/src/exynos" ]