phy: ti: omap-usb2: Fix the kernel-doc style

The documentaion uses incorrect style, so fix that.

drivers/phy/ti/phy-omap-usb2.c:102: warning: Function parameter or member 'comparator' not described in 'omap_usb2_set_comparator'

While at it, use a single line for function description

Signed-off-by: Vinod Koul <vkoul@kernel.org>