phy: rockchip: inno-usb2: Add missing clkout_ctl_phy kerneldoc

Add the missing documentation for the newly added clkout_ctl_phy field.

Fixes: 2775541de058 ("phy: rockchip: inno-usb2: Add clkout_ctl_phy support")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202605150315.MyBNQOPB-lkp@intel.com/
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20260520102859.1357411-1-heiko@sntech.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>