USB / dwc3: Fix three doc-build warnings

Two kerneldoc comments in gadget.c have excess function parameter description or wrong
prototype name and one kerneldoc comment in core.c has an excess function parameter
description, resulting in these three doc-build warnings:

   1. ./drivers/usb/dwc3/gadget.c:675: warning: Excess function parameter
        'nfifos' description in 'dwc3_gadget_calc_tx_fifo_size'
   2. ./drivers/usb/dwc3/gadget.c:700: warning: expecting prototype for
        dwc3_gadget_clear_tx_fifo_size(). Prototype was for dwc3_gadget_clear_tx_fifos()
        instead
   3. ./drivers/usb/dwc3/core.c:347: warning: Excess function parameter 'ref_clk_per'
        description in 'dwc3_ref_clk_period'

Fix the warnings by correcting the prototype name and removing excess parameter descriptions.
Signed-off-by: Kushagra Verma <kushagra765@outlook.com>
Link: https://lore.kernel.org/r/SI2PR01MB392995043CACD80884A13764F81C9@SI2PR01MB3929.apcprd01.prod.exchangelabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/core.c

@@ -341,7 +341,6 @@ static void dwc3_frame_length_adjustment(struct dwc3 *dwc)
  *		from the default, this will set clock period in DWC3_GUCTL
  *		register.
  * @dwc: Pointer to our controller context structure
- * @ref_clk_per: reference clock period in ns
  */
 static void dwc3_ref_clk_period(struct dwc3 *dwc)
 {

drivers/usb/dwc3/gadget.c

@@ -657,7 +657,6 @@ static int dwc3_gadget_set_ep_config(struct dwc3_ep *dep, unsigned int action)
 /**
  * dwc3_gadget_calc_tx_fifo_size - calculates the txfifo size value
  * @dwc: pointer to the DWC3 context
- * @nfifos: number of fifos to calculate for
  *
  * Calculates the size value based on the equation below:
  *
@@ -690,7 +689,7 @@ static int dwc3_gadget_calc_tx_fifo_size(struct dwc3 *dwc, int mult)
 }
 
 /**
- * dwc3_gadget_clear_tx_fifo_size - Clears txfifo allocation
+ * dwc3_gadget_clear_tx_fifos - Clears txfifo allocation
  * @dwc: pointer to the DWC3 context
  *
  * Iterates through all the endpoint registers and clears the previous txfifo