hsa: vpp_echo fifo size is u32

hsa: vpp_echo fifo size is u32

- Fix cli / config fifo size to only accept u32
  size input.
- Make cli / config fifo-size input type handling
  to be the same as vpp hoststack
- Clean up vpp_echo usage output
- Clean up json close stats labels to make them
  less confusing

Type: fix

Change-Id: I3aa2247f75a4ce284be9e7c0adc71ba488bfbf2b
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>