mISDN: Update parameter type of dsp_cmx_send()

mISDN: Update parameter type of dsp_cmx_send()

When booting a kernel with CONFIG_MISDN_DSP=y and CONFIG_CFI_CLANG=y,
there is a failure when dsp_cmx_send() is called indirectly from
call_timer_fn():

  [    0.371412] CFI failure at call_timer_fn+0x2f/0x150 (target: dsp_cmx_send+0x0/0x530; expected type: 0x92ada1e9)

The function pointer prototype that call_timer_fn() expects is

  void (*fn)(struct timer_list *)

whereas dsp_cmx_send() has a parameter type of 'void *', which causes
the control flow integrity checks to fail because the parameter types do
not match.

Change dsp_cmx_send()'s parameter type to be 'struct timer_list' to
match the expected prototype. The argument is unused anyways, so this
has no functional change, aside from avoiding the CFI failure.

Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202308020936.58787e6c-oliver.sang@intel.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Fixes: e313ac12eb13 ("mISDN: Convert timers to use timer_setup()")
Link: https://lore.kernel.org/r/20230802-fix-dsp_cmx_send-cfi-failure-v1-1-2f2e79b0178d@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>