fvp_utils.sh: Double-quote interactive "command" keys for LAVA jobs

Command content may include escapes like "\r", and these must be included
in properly quoted strings in YAML syntax to work as expected.

This issue was found while working with lava-expect/spm-edk2-uart0.exp
script.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I603b1ed9cfa6dba6058c632c46ca5ce4ff40dc6c
diff --git a/fvp_utils.sh b/fvp_utils.sh
index a7f4169..5265c50 100644
--- a/fvp_utils.sh
+++ b/fvp_utils.sh
@@ -760,7 +760,7 @@
                             for c in ${commands}; do
                                 cat <<EOF
      - name: interactive_command_${uart_number}_${key}
-       command: $c
+       command: "$c"
 EOF
                             done
                         fi
@@ -796,7 +796,7 @@
                             for c in ${commands}; do
                                 cat <<EOF
      - name: interactive_command_${uart_number}_${key}
-       command: $c
+       command: "$c"
 EOF
                             done
                         fi
@@ -824,7 +824,7 @@
                             for c in ${commands}; do
                                 cat <<EOF
      - name: interactive_command_${uart_number}_${key}
-       command: $c
+       command: "$c"
 EOF
                             done
                         fi
@@ -851,7 +851,7 @@
                             for c in ${commands}; do
                                 cat <<EOF
      - name: interactive_command_${uart_number}_${key}
-       command: $c
+       command: "$c"
 EOF
                             done
                         fi