cifs: print all credit counters in DebugData

Output of /proc/fs/cifs/DebugData shows only the per-connection
counter for the number of credits of regular type. i.e. the
credits reserved for echo and oplocks are not displayed.

There have been situations recently where having this info
would have been useful. This change prints the credit counters
of all three types: regular, echo, oplocks.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>