Staging: Remove staging/poch

Remove staging/poch.

Reasons for removal are -- The driver has serious cache
issues, that I couldn't fix. The card vendor is working
on a better replacement for the driver. The driver has
been delayed a lot and development has come to a stand
still.

Signed-off-by: Vijay Kumar B. <vijaykumar@bravegnu.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>