vmstat: fix meminfo unit

[Bluemangoo]

• fix Fix wrong unit of meminfo parser #667

Use a simple but not very graceful way to fix the issue.

See more in the issue.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 24 lines in your changes missing coverage. Please review.
✅ Project coverage is 19.16%. Comparing base (ee98c0a) to head (537edf5).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/uu/vmstat/src/parser.rs	0.00%	24 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #668      +/-   ##
==========================================
- Coverage   19.19%   19.16%   -0.03%     
==========================================
  Files          68       68              
  Lines       10135    10147      +12     
  Branches      545      545              
==========================================
  Hits         1945     1945              
- Misses       8190     8202      +12     

Flag	Coverage Δ
macos_latest	6.74% <ø> (ø)
ubuntu_latest	19.52% <0.00%> (-0.03%)	⬇️
windows_latest	0.02% <ø> (ø)

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[Franklin-Qi]

LGTM 💯