Fix the comment for POINT_CONVERSION_UNCOMPRESSED

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

RT#3838

(Imported from upstream's 41fe7d2380617da515581503490f1467ee75a521.)

Change-Id: I35745cd2a5a32bd726cb4d3c0613cef2bcbef35b
Reviewed-on: https://boringssl-review.googlesource.com/5946
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/ec.h b/include/openssl/ec.h
index f664211..004c949 100644
--- a/include/openssl/ec.h
+++ b/include/openssl/ec.h
@@ -87,7 +87,7 @@
 	/** 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
 } point_conversion_form_t;