Problem: duplicated feemarket params load

[yihuang]

The param loading is a significant source of memory allocations, reduce it as much as possible.

ref: #429

Description

---

For contributor use:

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

---

For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[codecov]

Codecov Report

Attention: Patch coverage is 72.72727% with 21 lines in your changes are missing coverage. Please review.

Project coverage is 63.15%. Comparing base (d97ce05) to head (78e5c7c).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #430      +/-   ##
===========================================
- Coverage    63.28%   63.15%   -0.14%     
===========================================
  Files          130      130              
  Lines        12348    12375      +27     
===========================================
+ Hits          7815     7816       +1     
- Misses        4017     4042      +25     
- Partials       516      517       +1     

Files	Coverage Δ
app/ante/eip712.go	60.86% <100.00%> (+0.96%)	⬆️
app/ante/fee_checker.go	90.81% <100.00%> (-0.19%)	⬇️
app/ante/fee_market.go	73.91% <100.00%> (+1.18%)	⬆️
app/ante/fees.go	80.99% <100.00%> (-0.83%)	⬇️
app/ante/handler_options.go	79.72% <100.00%> (+1.78%)	⬆️
app/app.go	84.13% <100.00%> (ø)
x/evm/keeper/config.go	94.23% <100.00%> (+1.20%)	⬆️
x/evm/keeper/keeper.go	89.28% <ø> (+1.85%)	⬆️
x/evm/keeper/statedb.go	86.29% <100.00%> (-0.11%)	⬇️
x/feemarket/keeper/params.go	51.35% <ø> (-13.65%)	⬇️
... and 4 more

... and 1 file with indirect coverage changes