camcontrol: Include stdbool.h rather than relying on namespace pollution

I have several environments, and at least one of them fails to build
because bool is undefined. Since we use bool, always include stdbool.h
rather than relying on any indirect definitions to pull it in.

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sbin/camcontrol/camcontrol.c

@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/endian.h>
 #include <sys/sbuf.h>
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>