hal/sparcv8leon3: fix exception handling

[lukileczo]

JIRA: RTOS-615

Description

• Fix exceptions number calculation
• Fix page fault handling

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: sparcv8leon3-gr712rc-board.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[github-actions]

Unit Test Results

5 995 tests  +6   5 354 ✔️ +6   30m 0s ⏱️ +2s
   339 suites +6      641 💤 ±0 
       1 files   ±0          0 ❌ ±0 

Results for commit 5312a7e. ± Comparison against base commit 5f3dd1e.