intel/broadwell: free local heap object

No real harm done (thanks to our free() implementation),
but let's do it right.

Change-Id: Ib98d28aabc043dff5c288728c33490a79f09f35a
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Found-by: Coverity Scan
Reviewed-on: http://review.coreboot.org/8511
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/soc/intel/broadwell/me.c

@@ -998,6 +998,7 @@ static int intel_me_read_mbp(me_bios_payload *mbp_data, device_t dev)
 	}
 	#undef ASSIGN_FIELD_PTR
 
+	free(mbp);
 	return 0;
 
 mbp_failure: