opp: Fix some kernel-doc comments

Make @freq to @bw in dev_pm_opp_find_bw_ceil() and
dev_pm_opp_find_bw_floor() kernel-doc comment to
remove warnings found by running scripts/kernel-doc,
which is caused by using 'make W=1'.

drivers/opp/core.c:753: warning: Function parameter or member 'bw' not
described in 'dev_pm_opp_find_bw_ceil'
drivers/opp/core.c:753: warning: Excess function parameter 'freq'
description in 'dev_pm_opp_find_bw_ceil'
drivers/opp/core.c:812: warning: Function parameter or member 'bw' not
described in 'dev_pm_opp_find_bw_floor'
drivers/opp/core.c:812: warning: Excess function parameter 'freq'
description in 'dev_pm_opp_find_bw_floor'
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/core.c

@@ -732,7 +732,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_level_ceil);
 /**
  * dev_pm_opp_find_bw_ceil() - Search for a rounded ceil bandwidth
  * @dev:	device for which we do this operation
- * @freq:	start bandwidth
+ * @bw:	start bandwidth
  * @index:	which bandwidth to compare, in case of OPPs with several values
  *
  * Search for the matching floor *available* OPP from a starting bandwidth
@@ -791,7 +791,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_bw_ceil);
 /**
  * dev_pm_opp_find_bw_floor() - Search for a rounded floor bandwidth
  * @dev:	device for which we do this operation
- * @freq:	start bandwidth
+ * @bw:	start bandwidth
  * @index:	which bandwidth to compare, in case of OPPs with several values
  *
  * Search for the matching floor *available* OPP from a starting bandwidth