yamllint: fix all yamllint colons, commas and empty-lines errors

Fix all colons and commas errors detected by yamllint:

yamllint -f parsable -c .yamllint $( find -regex '.*\.y[a]*ml' ) | \
  grep '(brackets)'

yamllint -f parsable -c .yamllint $( find -regex '.*\.y[a]*ml' ) | \
  grep '(commas)'

yamllint -f parsable -c .yamllint $( find -regex '.*\.y[a]*ml' ) | \
  grep '(empty-lines)'

Default config is no space before, one space after, max 2 empty lines.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>

boards/arm64/mimx93_evk/mimx93_evk_a55.yaml

@@ -5,7 +5,7 @@ arch: arm64
 toolchain:
   - zephyr
   - cross-compile
-ram:  1024
+ram: 1024
 testing:
   ignore_tags:
     - net