staging: line6: drop ToneportSourceInfo CamelCase name

Fix the following checkpatch.pl warning:

  WARNING: Avoid CamelCase: <ToneportSourceInfo>
  #5383: FILE: staging/line6/toneport.c:90:
  +struct ToneportSourceInfo {

Since the struct is only used to define the global
toneport_source_info[] table, I have chosen to make the struct
anonymous and part of the table definition.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>