chandata: cast int to uint16 instead opposite in IsChannelData
chandata: cast int to uint16 instead opposite in IsChannelData

Before:
BenchmarkIsChannelData-12    	2000000000	         1.73 ns/op	6350.93 MB/s	       0 B/op	       0 allocs/op

After:
BenchmarkIsChannelData-12    	2000000000	         1.64 ns/op	6698.72 MB/s	       0 B/op	       0 allocs/op

ernado/turn