afs: fix kernel_write / kernel_read arguments

afs: fix kernel_write / kernel_read arguments

The order / content of the arguments passed to kernel_write and
kernel_read are not right. As a result, the kernel will panic if one of
the functions in question is called.

[kaduk@mit.edu: include configure check for multiple kernel_read()
variants, per linux commits bdd1d2d3d251c65b74ac4493e08db18971c09240
and e13ec939e96b13e664bb6cee361cc976a0ee621a]

FIXES 134440

Change-Id: I4753dee61f1b986bbe6a12b5568d1a8db30c65f8
Reviewed-on: https://gerrit.openafs.org/12769
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>