ni-utils: adjust nisetbootmode.functions for xilinx-zynqhf
ni-utils: adjust nisetbootmode.functions for xilinx-zynqhf

For xilinx-zynqhf targets use the exported scratch_hardreset attribute
instead of the bootmode cpld register.
The bootmodes are represented by the following values:
00 - default
01 - safemode (not used, but the U-Boot env requires it in readbootmode)
02 - restore
03 - auto-restore
The bootmode file is not used anymore, the nisetbootmode will only
set and read the scratch_hardreset attribute.

Signed-off-by: Arnold Csorvasi <b0f066b649ab9fcbb2512e9156d597e1cbade61e@ni.com>

ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt