meson: Fix coding style when declaring arrays

The meson.build files mix array declarations with and without a space
after the opening and before the closing square bracket. The vast
majority of cases don't use spaces, so standardize on that.

While it it, fix indentation in a few places.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

test/process/meson.build

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: CC0-1.0
 
 process_tests = [
-    [ 'process_test',  'process_test.cpp' ],
+    ['process_test',   'process_test.cpp'],
 ]
 
 foreach t : process_tests