prov/rxm: Correct pad in RXM wire protocol structure (#35)

Pad causes wasteful alignment. The Verbs experimental XRC implementation
uses some of the wasted space.

Signed-off-by: Steve Welch <swelch@systemfabricworks.com>

prov/rxm/src/rxm.h

@@ -136,7 +136,7 @@ struct rxm_ep_wire_proto {
 	uint8_t	ctrl_version;
 	uint8_t	op_version;
 	uint8_t endianness;
-	uint8_t padding[6];
+	uint8_t padding[5];
 	uint64_t eager_size;
 };