[PATCH] USBATM: measure buffer size in bytes; force valid sizes

Change the module parameters rcv_buf_size and snd_buf_size to
specify buffer sizes in bytes rather than ATM cells.  Since
there is some danger that users may not notice this change,
the parameters are renamed to rcv_buf_bytes etc.  The transmit
buffer needs to be a multiple of the ATM cell size in length,
while the receive buffer should be a multiple of the endpoint
maxpacket size (this wasn't enforced before, which causes trouble
with isochronous transfers), so enforce these restrictions.  Now
that the usbatm probe method inspects the endpoint maxpacket size,
minidriver bind routines need to set the correct alternate setting
for the interface in their bind routine.  This is the reason for
the speedtch changes.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>