usb: drop comment about 2 uhci drivers

Drop the ancient comment about 2 usb/uhci drivers since there are
no longer 2 of them.

Cc: Johan Hovold <[e-mail]>
Cc: [e-mail]
Signed-off-by: Randy Dunlap <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/serial/Kconfig

···
 	  parallel port on the USB 2 appears as a third serial port on Linux.
 	  The Digi Acceleport USB 8 is not yet supported by this driver.
 
-	  This driver works under SMP with the usb-uhci driver.  It does not
-	  work under SMP with the uhci driver.
-
 	  To compile this driver as a module, choose M here: the
 	  module will be called digi_acceleport.