Revert "objtool: Increase per-function WARN_FUNC() rate limit"

This reverts commit 0a7fb6f0.

The "skipping duplicate warnings" warning is technically not an actual
warning, which can cause confusion.  This feature isn't all that useful
anyway.  It's exceedingly rare for a function to have more than one
unrelated warning.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/e5abe5e858acf1a9207a5dfa0f37d17ac9dca872.1743481539.git.jpoimboe@kernel.org