objtool: Silence more KCOV warnings

objtool: Silence more KCOV warnings

[ Upstream commit 6b023c7842048c4bbeede802f3cf36b96c7a8b25 ]

In the past there were issues with KCOV triggering unreachable
instruction warnings, which is why unreachable warnings are now disabled
with CONFIG_KCOV.

Now some new KCOV warnings are showing up with GCC 14:

  vmlinux.o: warning: objtool: cpuset_write_resmask() falls through to next function cpuset_update_active_cpus.cold()
  drivers/usb/core/driver.o: error: objtool: usb_deregister() falls through to next function usb_match_device()
  sound/soc/codecs/snd-soc-wcd934x.o: warning: objtool: .text.wcd934x_slim_irq_handler: unexpected end of section

All are caused by GCC KCOV not finishing an optimization, leaving behind
a never-taken conditional branch to a basic block which falls through to
the next function (or end of section).

At a high level this is similar to the unreachable warnings mentioned
above, in that KCOV isn't fully removing dead code.  Treat it the same
way by adding these to the list of warnings to ignore with CONFIG_KCOV.

Reported-by: Ingo Molnar <mingo@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
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/66a61a0b65d74e072d3dc02384e395edb2adc3c5.1742852846.git.jpoimboe@kernel.org
Closes: https://lore.kernel.org/Z9iTsI09AEBlxlHC@gmail.com
Closes: https://lore.kernel.org/oe-kbuild-all/202503180044.oH9gyPeg-lkp@intel.com/
Signed-off-by: Sasha Levin <sashal@kernel.org>