util/string: add ascii_to for unsigned short

Ref #2670

repos/base/include/util/string.h

@@ -342,6 +342,17 @@ namespace Genode {
 	}
 
 
+	/**
+	 * Read unsigned short value from string
+	 *
+	 * \return number of consumed characters
+	 */
+	inline size_t ascii_to(const char *s, unsigned short &result)
+	{
+		return ascii_to_unsigned(s, result, 0);
+	}
+
+
 	/**
 	 * Read unsigned long value from string
 	 *