vpp: T7068: Add range validation for unix poll-sleep-usec

[HollyGurza]

Change Summary

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Other (please describe):

Related Task(s)

• https://vyos.dev/T7068

Related PR(s)

Proposed changes

How to test

vyos@vyos:~$ conf
[edit]
vyos@vyos# set vpp settings interface eth1 driver dpdk 
[edit]
vyos@vyos# set vpp settings unix poll-sleep-usec 4294967295

  Number is not in any of allowed ranges
  
  
  
  Invalid value
  Value validation failed
  Set failed

[edit]
vyos@vyos# set vpp settings unix poll-sleep-usec 500000
[edit]
vyos@vyos# commit
[ vpp ]
WARNING: offload option in eth1 settings is not supported by VPP interfaces. It will be ignored.

[edit]
vyos@vyos# run show interfaces 
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface    IP Address          MAC                VRF        MTU  S/L    Description
-----------  ------------------  -----------------  -------  -----  -----  -------------
eth0         192.168.122.138/24  0c:02:eb:68:00:00  default   1500  u/u    OUT
eth1         10.0.0.1/24         0c:02:eb:68:00:01  default   1500  u/u    INSIDE
eth2         -                   0c:02:eb:68:00:02  default   1500  u/D
eth3         -                   0c:02:eb:68:00:03  default   1500  u/D
lo           127.0.0.1/8         00:00:00:00:00:00  default  65536  u/u
             ::1/128
[edit]

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[dmbaturin]

Suggested change

	<description>Microseconds to sleep</description>
	<description>Sleep interval in microseconds</description>

[HollyGurza]

done