GPTIMER: timer probing must not be on timer0

Timers are identical within one GPTIMER core. Probing only the
first timer is sufficient, however the first timer was hardcoded
to timer0 which is not correct in a multi-OS system like RTEMS
AMP. This patch makes sure that probing is done on the first
timer that can be used by this RTEMS instance. Without this
patch RTEMS AMP is broken on systems (like the GR712RC) where
there is only one GPTIMER core proviing multiple timers. Designs
(like the NGMP/FP) where there are multiple GPTIMER cores are not
affected.
DEVFS mknod stored path pointer, now path is copied instead
GRETH: avoid hw generated UDP/TCP cksum generation

Hardware generated checksum UDP packets does not work for
IP fragmented UDP packets. It seems as if the BSD stack never
signals to the GRETH driver to generate or not to generate
TCP/UDP checksum for different cases. The GRETH driver never
tells the BSD stack about it capabilities either so there is
no point generating the cksums in HW when its done in SW any
way.

This patch disables hardware generated UDP and TCP checksums.
GRETH: avoid hw generated UDP/TCP cksum generation

Hardware generated checksum UDP packets does not work for
IP fragmented UDP packets. It seems as if the BSD stack never
signals to the GRETH driver to generate or not to generate
TCP/UDP checksum for different cases. The GRETH driver never
tells the BSD stack about it capabilities either so there is
no point generating the cksums in HW when its done in SW any
way.

This patch disables hardware generated UDP and TCP checksums.