bugs/core: Pass down the condition string of WARN_ON_ONCE(cond) warnings to __WARN_FL...

bugs/core: Pass down the condition string of WARN_ON_ONCE(cond) warnings to __WARN_FLAGS()

Doing this will allow architecture code to store and print out
this information as part of the WARN_ON and BUG_ON facilities.

The format of the string is '[condition]', for example:

  WARN_ON_ONCE(idx < 0 && ptr);

Will get the '[idx < 0 && ptr]' string literal passed down as 'cond_str'
in __WARN_FLAGS().

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/r/20250515124644.2958810-3-mingo@kernel.org