clk: imx: Fix and update kerneldoc

Fix and add missing kerneldoc to fix compile warnings like:

  drivers/clk/imx/clk-pfd.c:27: warning: Function parameter or member 'hw' not described in 'clk_pfd'
  drivers/clk/imx/clk-pllv3.c:53: warning: Function parameter or member 'ref_clock' not described in 'clk_pllv3'

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

drivers/clk/imx/clk-pfd.c

@@ -12,7 +12,7 @@
 
 /**
  * struct clk_pfd - IMX PFD clock
- * @clk_hw:	clock source
+ * @hw:		clock source
  * @reg:	PFD register address
  * @idx:	the index of PFD encoded in the register
  *

drivers/clk/imx/clk-pfdv2.c

@@ -17,7 +17,7 @@
 
 /**
  * struct clk_pfdv2 - IMX PFD clock
- * @clk_hw:	clock source
+ * @hw:		clock source
  * @reg:	PFD register address
  * @gate_bit:	Gate bit offset
  * @vld_bit:	Valid bit offset

drivers/clk/imx/clk-pllv3.c

@@ -30,12 +30,15 @@
 
 /**
  * struct clk_pllv3 - IMX PLL clock version 3
- * @clk_hw:	 clock source
+ * @hw:		clock source
  * @base:	 base address of PLL registers
  * @power_bit:	 pll power bit mask
  * @powerup_set: set power_bit to power up the PLL
  * @div_mask:	 mask of divider bits
  * @div_shift:	 shift of divider bits
+ * @ref_clock:	reference clock rate
+ * @num_offset:	num register offset
+ * @denom_offset: denom register offset
  *
  * IMX PLL clock version 3, found on i.MX6 series.  Divider for pllv3
  * is actually a multiplier, and always sits at bit 0.