Staging: Add SBE 2T3E3 WAN driver

This is a driver for SBE Inc.'s dual port T3/E3 WAN cards. Based on
their original GPLed driver.

The original driver tarball is now accessible at
http://userweb.kernel.org/~chris/SBE_2T3_Linux_2.0c.tgz



It needs at least a new generic HDLC setup code (not yet written) before
moving to drivers/net/wan.

Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>