staging: vt6655: remove fragmentation from driver

fragmentation is now handled by mac80211.

Remove functions
device_alloc_frag_buf
device_init_defrag_cb
device_free_frag_buf

Removing
typedef struct tagSDeFragControlBlock
frag_thresh
sRxDFCB
cbDFCB;
cbFreeDFCB;
uCurrentDFCBIdx;

macros
FRAG_THRESH_MIN
FRAG_THRESH_MAX

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>