compiler-context-analysis: Remove Sparse support

compiler-context-analysis: Remove Sparse support

Remove Sparse support as discussed at [1].

The kernel codebase is still scattered with numerous places that try to
appease Sparse's context tracking ("annotation for sparse", "fake out
sparse", "work around sparse", etc.). Eventually, as more subsystems
enable Clang's context analysis, these places will show up and need
adjustment or removal of the workarounds altogether.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250207083335.GW7145@noisy.programming.kicks-ass.net/
Link: https://lore.kernel.org/all/Z6XTKTo_LMj9KmbY@elver.google.com/
Link: https://patch.msgid.link/20251219154418.3592607-24-elver@google.com