pwm: linux/pwm.h: fix Excess kernel-doc description warning

Remove the @pwm: line to prevent the kernel-doc warning:

include/linux/pwm.h:87: warning: Excess struct member 'pwm' description in 'pwm_device'

Signed-off-by: Randy Dunlap <[e-mail]>
Cc: Thierry Reding <[e-mail]>
Cc: Uwe Kleine-König <[e-mail]>
Cc: <[e-mail]>
Fixes: f3e25e68ceb2 ("pwm: Drop unused member "pwm" from struct pwm_device")
Reviewed-by: Uwe Kleine-König <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

include/linux/pwm.h

···
  * @label: name of the PWM device
  * @flags: flags associated with the PWM device
  * @hwpwm: per-chip relative index of the PWM device
- * @pwm: global index of the PWM device
  * @chip: PWM chip providing this PWM device
  * @args: PWM arguments
  * @state: last applied state