Documentation: util/board_status/README formatting

Improve markdown formatting.
Split paragraphs to avoid too long text.

Change-Id: Ia3a74460a49f28301c5e2e3b061aeb1e0eeb6c16
Signed-off-by: Alexey Vazhnov <vazhnov@boot-keys.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50637
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

util/board_status/board_status.sh

@@ -32,11 +32,11 @@ case $(uname) in
 			echo "Please install gmake, or build and install devel/gmake from ports."
 			exit $EXIT_FAILURE
 		else
-			MAKE=gmake
+			MAKE='gmake'
 		fi
 		;;
 	*)
-		MAKE=make
+		MAKE='make'
 		;;
 esac