usb: host: ehci-omap: Provide documentation for ehci_hcd_omap_probe()'s arg 'pdev'

usb: host: ehci-omap: Provide documentation for ehci_hcd_omap_probe()'s arg 'pdev'

Description for 'pdev' argument was missing from the function header.

Fixes the following W=1 warning:

 drivers/usb/host/ehci-omap.c:87: warning: Function parameter or member 'pdev' not described in 'ehci_hcd_omap_probe'

Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Vikram Pandita <vikram.pandita@ti.com>
Cc: Anand Gadiyar <gadiyar@ti.com>
Cc: Keshava Munegowda <keshava_mgowda@ti.com>
Cc: Roger Quadros <rogerq@ti.com>
Cc: Felipe Balbi <felipe.balbi@nokia.com>
Cc: linux-omap@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200702144625.2533530-13-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>