usb/host/fotg210: Add function: output_buf_tds_dir()

checkpatch complains about too many leading tabs because the switch
statement starts after 6 tabs.

fill_periodic_buffer() -> for() -> do -> switch() -> if() ->
list_for_each_entry() and finally the last switch().

This patch moves the list_for_each_entry() and the last switch() to a
new function named output_buf_tds_dir(). This change makes the code
easier to read and calm down checkpatch. This patch changes it to:

fill_periodic_buffer() -> for() -> do -> switch() -> if() ->
output_buf_tds_dir()

Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>