misc Makefile clean up for cocotb CI testing

[ruck314]

Description

• removed BUILD_SVR_TYPE as it is already defined in ruckus/system_shared.mk
• clean up on the GHDL_VERSION string
• reformating the BUILD_STRING to match the Vivado string of BUILD_STRING
• vhdeps fix to missing Chksum component
• Multiple fixes found using ghdl -a

[codecov-commenter]

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 36.41%. Comparing base (9a929de) to head (4e018ab).
⚠️ Report is 191 commits behind head on pre-release.
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Additional details and impacted files

@@               Coverage Diff               @@
##           pre-release    #1376      +/-   ##
===============================================
- Coverage        36.44%   36.41%   -0.04%     
===============================================
  Files               25       27       +2     
  Lines             1199     1373     +174     
===============================================
+ Hits               437      500      +63     
- Misses             762      873     +111     

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