uio driver: do not map the shared memory in the kernel

The shared memory region is not accessed from within the kernel, no need
to map and unmap it.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
uio driver: add memory region names for sysfs

Signed-off-by: Henning Schild <henning.schild@siemens.com>