staging: gasket: page table: remove code for "no dma_ops"

Remove code with TODOs on it for working around apparent problems
previously seen in a qemu environment where dma_ops was not set
correctly.  There is no user of this in the current code.

Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>