Fix the comment for POINT_CONVERSION_UNCOMPRESSED

The |z| value should be 0x04 not 0x02

RT#3838
Signed-off-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NEmilia Käsper <emilia@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>

include/openssl/ec.h

@@ -106,7 +106,7 @@ typedef enum {
         /** the point is encoded as z||x, where the octet z specifies
          *  which solution of the quadratic equation y is  */
     POINT_CONVERSION_COMPRESSED = 2,
-        /** the point is encoded as z||x||y, where z is the octet 0x02  */
+        /** the point is encoded as z||x||y, where z is the octet 0x04  */
     POINT_CONVERSION_UNCOMPRESSED = 4,
         /** the point is encoded as z||x||y, where the octet z specifies
          *  which solution of the quadratic equation y is  */