regulator: fix kernel-doc for regulator_suspend()

Fix kernel-doc warning:

../drivers/regulator/core.c:4479: warning: Excess function parameter 'state' description in 'regulator_suspend'

Signed-off-by: Randy Dunlap <[e-mail]>
Cc: Liam Girdwood <[e-mail]>
Cc: Mark Brown <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/core.c

···
 #ifdef CONFIG_SUSPEND
 /**
  * regulator_suspend - prepare regulators for system wide suspend
- * @state: system suspend state
+ * @dev: ``&struct device`` pointer that is passed to _regulator_suspend()
  *
  * Configure each regulator with it's suspend operating parameters for state.
  */