bcc/tools: use device number and inode number to identify a file
bcc/tools: use device number and inode number to identify a file

Currently, the filetop tool use (tid, filename, type) tuple to
key a file, which is not enough to uniquely identify a file.
A thread write to multi files with the same name would add up to
same value in the map which can be repro by the following command:

$ cat somefile | tee /foo/bar/xxx /fuz/baz/xxx

Let us add device number and inode number to uniquely identify
a file.

Signed-off-by: Hengqi Chen <2146682b4c3fe4aa97c809745b7d5be9e6165e06@outlook.com>

brendangregg/bcc,brendangregg/bcc,iovisor/bcc,brendangregg/bcc,iovisor/bcc,brendangregg/bcc,brendangregg/bcc,iovisor/bcc,iovisor/bcc,iovisor/bcc